Light Review: Nitecore TM20K – 20,000 Lumens!

Nitecore’s Tiny Monsters have always been punchy performers, from the first one I tested, (the TM11) all the way through to another Monster light that is Tiny compared to its output. Join me in this Nitecore TM20K review, 20K being the 20,000 Lumens, yes, 20,000 Lumens output from a palm sized light. As well as a look round the TM20K, this review includes output measurements, runtime graphs, and beamshots to give you the true story of its performance. It really is a Monster!

Video Overview

This video is an overview of the TM20K with a first look over the light before we get onto more details and the measurements.

What is in the box?:
This gallery shows the TM20K’s packaging and what is included. The holstered TM20K, a USB-C charging cable, a lanyard, and a thin cord for threading the lanyard.
There is also a look over the belt holster and how the top flap opens.

A good look round the TM20K – Things to look out for here are:
First, do not turn the TM20K straight on out of the box! There is a blue protective plastic film over the lens that will melt and make a mess of the front of the light, so make sure to take this off.
The body of the TM20K is a single piece, and this is not broken by any battery doors, as the TM20K has a built-in battery and is USB-C rechargeable.
The lanyard hole is next to the charging port and mode switch. On the opposite side to the mode switch is the selector toggle switch with lockout setting.
One of the flat sides has a wide steel belt clip. Also shown are the small heat sink fins and grip knurling.
On the tail of the TM20K you find the power button, tactical switches and the charging port.

The beam

Please be careful not to judge tint based on images you see on a computer screen. Unless properly calibrated, the screen itself will change the perceived tint.

The indoor beamshot is intended to give an idea of the beam shape/quality rather than tint. All beamshots are taken using daylight white balance. The woodwork (stairs and skirting) are painted Farrow & Ball “Off-White”, and the walls are a light sandy colour called ‘String’ again by Farrow & Ball. I don’t actually have a ‘white wall’ in the house to use for this, and my wife won’t have one!

For the beamshot comparison I used three output modes. The Daily mode ‘Floodlight’ and ‘Spotlight’ special output levels plus the ‘Turbo’ 20,000 Lumen mode.

Indoors are only the ‘Floodlight’ and ‘Spotlight’ modes as Turbo is too bright. Then moving outdoors with the same modes (around the 2,000 Lumen level), and then with the same exposure, the Turbo output. 20,000 lumens really lights things up!!

Batteries and output:

The TM20K runs on a built in battery made of 2 x 21700 4800mAh cells.

Please note, all quoted lumen figures are from a DIY integrating sphere, and according to ANSI standards. Although every effort is made to give as accurate a result as possible, they should be taken as an estimate only. The results can be used to compare outputs in this review and others I have published.

19 XP-L2 LEDs to blast out 20,000 lumens.

When working with any lights with an output over 5,000 lumens, I need to make modifications to the integrating sphere. For the TM20K, due to the extreme output and small size, it is limited to short bursts of the 20,000 lumen Turbo output. So the output table is a little different to most of the reviews I carry out.

Half the table is normal, then where it starts to list an ND filter, this is a ‘neutral density’ filter that simply cuts the light reaching the sensor by approximately 90%. Reference readings are taken to ensure the filter factor is correct, and a set of measurements were taken. With the short 8s burst of Turbo, several readings were taken and averaged. All of this is included in the table.

The graphs in this gallery show a few different things. First is a trace of the charging current consumed when charging the TM20K.
Next up is the runtime trace for High output. Due to the Turbo output being a burst mode only, for the full runtime, the graph shows the output for the high output level.
Now we have two copies of the same graph, the first shows all the traces taken to check the behaviour during the ANSI 30 second measurement time.

Shown first is an initial ‘High’ ANSI output trace (Section 1), then the Turbo button held for 30s (Section 2) where the output drops to High after 8s. Section 3 shows what happens when you intentionally use Burst, Burst, Burst until the TM20K won’t output Turbo any more.

As the ANSI output should be measured at 30s, the 8s Turbo output would mean ‘ANSI Turbo’ measurement was 3611 lm, so this means we can’t actually state an ANSI Turbo output and instead I have gone for ‘max at switch on’ for the value of Turbo, and this is what was used in the output table.

The TM20K in use

20,000 lumens in the palm of your hand, here it is:

And as a starting point I have to say the TM20K is scary bright! As well as that it heats up so quickly on Turbo you really know this is pumping out the power.

Being about the size of a 2x 18650 light used to be, the TM20K is noticeably heavier and more dense than this older class of light, a sign it is packed with performance.

The supplied holster is very nicely made and is a rigid style with flip-top lid style opening. When belt mounted you need to pull the holster body away from you to allow the lid to hinge open far enough to get the TM20K out. This might have worked better flipping open away from you. The magnetic closure is a nice touch and allows for silent opening (without the ‘tearing’ sound of Velcro).

One of the most important features for a light like this is the lockout; yes the ‘not outputting any light’ feature. Absolutely critical as the output is so high, if contained it will be dangerous.

Lockout should always be easier to activate than to deactivate, and Nitecore have made it very easy. Slide the toggle switch to the padlock and once it has been there for 2s the TM20K is locked.

While locked, if you slide the toggle to 1 or 2, the power button flashes five times to let you know it is locked. Unlocking requires two switches to be used at the same time. Holding the mode switch down as you slide the toggle switch from lockout to position 1 or 2 with the beam turning on briefly to let you know unlocking was successful.

All of that to talk about the TM20K not outputting anything, well, you will be very happy about this feature.

In terms of handling and the interface, although the TM20K lists ‘tactical’ modes, the layout of buttons and ease of access to them would not be my choice for use in a pressured situation. General use, and even search and rescue use, but not reaction or time critical scenarios where you might miss buttons or press ones you didn’t mean to.

Onto those 20,000 lumens. You get a burst of 8s at this level. If you immediately reactivate Turbo, you can do this two further times (three times before a cooling off period) where the thermal protection prevents the TM20K from going above High mode even using the Turbo button. So from cold, 24 consecutive seconds of 20,000 lumen output. Measured and confirmed as shown in the output table and graphs, all from a palm sized light. This is seriously impressive.

Going to the other extreme, I would have preferred a mode lower than 350lm. This is the ‘ultra-low’ mode on the TM20K. Even if you are breaking out the Tiny Monster, there is still a practical lower level for every day use and 350lm is too high, so this is a light to bring out when you want a lot of light.

Considering the size, that performance on High giving a hour of solid output, 45 minutes of which is over 3000lm, does make this a workhorse, even if you ignore the Turbo output.

Not forgetting my previous comments about the tactical mode, the momentary output in this mode is great for searching especially when other people are around and you don’t want to blind them.

My preference is always for removable/replaceable batteries, but the other side to this is the guaranteed performance of the cells chosen by Nitecore to power this Tiny Monster, and the simplification of the design as it doesn’t need a battery door. Being a super high performance light, the cell characteristics are critical, so we can take the built-in cells as a positive point.

20,000 lumens is shocking and astounding from a pocket sized light, well done Nitecore.

Review Summary
The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond that covered in the review.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

What doesn’t work so well for me

‘Ultra-low’ mode is still 350 lumens.
Holster lid opening into your body is a bit awkward.

Things I like

20,000 Lumen burst output.
Excellent Lockout implementation.
Momentary and latching operation.
Fixed Flood and Spot special modes.
Instant access twin Turbo switches.
Very compact for the output performance.
Quality holster included.
19 XP-L2 LEDs.

Gear Review: HORL 2 Knife Sharpener

HORL 1993 are creating a revolution in sharpening with their innovative line of rolling knife sharpeners. Many of you will likely have seen their system popping up in various social media feeds, especially if you have any interests involving knives. Though primarily aimed at sharpening kitchen knives, having given the system a quick try out at IWA 2022, I was intrigued to test it in more depth and with other types of knives. Join me in this HORL 2 knife sharpener review for a closer look at this new approach to guided sharpening.

What is on test?:

For this review, on test are the HORL 2 sharpener with add-on Premium Sharpening kit plus the storage block. HORL also sent the tea towel and branded plasters.

A good look round the HORL 2 – Things to look out for here are:
In this first part which includes the HORL 2 sharpener plus the optional storage block, I’m breaking it into three sections. First the HORL 2 box and first look over the knife holder / angle guide, then views all round the storage block, and finally the rolling sharpening stone itself.

Inside the box are a couple of printed guides, and the two main components, the rolling sharpener and the magnetic guide block. The precisely finished wooden guide block has two angled ends, 15 degrees and 20 degrees. The ends are marked with their angle and have a rubber surface to cushion and hold the knife.

An optional extra that goes with the sharpener so well you really should get it, is the storage block. Available in either of the two woods used for the sharpeners themselves you can match the sharpener or go with a wood contrast. The block has two cut-outs, one is an angled pocket to sit the rolling sharpener in, and the other is a slot that has a couple of bolt heads which the magnetic guide block grabs on to. The quality of finish is very high.

Lastly in this detailed look at the components is the rolling sharpener itself. A cylinder with a round sharpening stone at each end.
The wooden centre grip section of the rolling sharpener is in the matching wood to the guide block, and rotates freely. At each end are rubber rings to act as wheels, and the sharpening disks. As it comes this includes a diamond disk and a grooved ceramic coated disk.
Also shown here is how the HORL 2 neatly sits on the storage block.

The Premium Sharpening Kit add-on:
Though you can produce a good edge with the standard HOLR 2, the premium sharpening kit is designed to further refine that edge and take it to another level.
The kit includes two extra sharpening disks of 3000 and 6000 grit. These are found inside matching storage tins, wrapped in a cloth square. As well as these two fine stones, you also have a thick leather strop for cleaning and deburring the edge.
The 3000 grit stone is blue and the finest 6000 grit stone is white. Both are marked on the back of the disk with the grit.

Changing the Stone:
Changing stones on the HORL 2 is simple. Grip the rubber wheel firmly and simply unscrew the stone you want to change; then screw in the replacement. My own preference was the diamond and 3000 grit as a pair.

Video overview and sharpening test.

This video takes detailed look at the HORL 2 being used for the first time on a Santoku kitchen knife and an outdoor / hunting knife. It is quite long but also uncovers a few tips and tricks you might be interested in as well as showing a reprofile of the edge angle. It is worth watching for the insights into how the sharpener interacts with parts of the knife and possible precautions you might want to take.

What it is like to use?

If you have watched the whole video you will have seen what I’m going to describe in this section for real. For this review I’m using the HORL 2 along with two optional extras, the storage block, and the premium sharpening kit with its finer grit stones and leather strop.

As the simplest and most basic look at using the HORL 2, these photos show how you set up the knife on the magnetic angle block with the roller sharpener against the knife edge. You can see how the edge-to-stone angle is maintained and allows sharpening by rolling the sharpener backwards and forwards.
Of note is that your kitchen work surface (or table) is used as part of the sharpening system because you need a large surface to working the rolling sharpener along the blade. Typically a sharpening system will contain the dust and metal filings produced to the sharpener, but the HORL 2 drops the filings that don’t stick to the magnetized blade all over the work surface. It is a bit of a messy eater when it comes to sharpening systems.

Beyond the basic operation of the HORL 2 here are a few general observations:

  • Operation is incredibly simple for use with most kitchen knives.
  • If the depth of the blade is more than the diameter of the sharpening disk you have to use ‘riser blocks’ (like a chopping board) to be able to sharpen the edge.
  • It is very easy to bump the sharpening stone into the knife bolster or handle. I use masking tape to protect these areas from damage.
  • You will magnetise the blade by using the magnetic angle guide block.
  • The sharpening dust collects on the magnetised blade and edge during use.
  • Shorter / narrower blades (paring knives or pocket knives) need very careful positioning on the angle block.
  • As your worktop is part of the sharpening system, this will be covered in metal filings

When swapping from a kitchen knife to an outdoor / hunting knife, it became apparent of an issue you need to work round regarding the tip of the knife.
With many hunting knives, the blade edge curves upward to meet the spine of the blade at the tip. This introduces challenges of maintaining the edge angle all through the sweep of the edge on any sharpening system. On the HORL 2 it requires the user to no longer rely on the angle block to provide the correct angle, instead the user has to twist the rolling sharpener to the correct angle at the tip.
Illustrated below is the angle the roller needs to be moved to sharpen this knife all the way to the tip. It is actually 20 degrees, the same angle as is used on the magnetic angle block. With the rubber wheels on the roller gripping the work surface, this does need the user to force the roller to twist round and get the hang of following the angle near the tip.
Another feature of a hunting knife verses a kitchen knife it that typically there is a ‘plunge line’ where the blade profile and ricasso meet. Also shown below are photos of how the corners of the HORL 2 stones hit the plunge line and might not quite reach the very end of the cutting edge. You will also likely mark the ricasso with the stone.
Finally with the grooved ceramic stone of the HORL 2 and the tip of a knife with a curve there is a possibility of the edge catching into the groove. This happened a couple of times in the video when turning the sharpener to work the tip of the blade, and prompted me to abandon the ceramic stone for a blade with curved tip like this. For kitchen knives this was not an issue.

Review Summary

The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond that covered in the review.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

I’m starting with what doesn’t work so well, so I can finish on a more positive note

What doesn’t work so well for me

  • Needs ‘riser blocks’ for blades wider than the sharpening disk.
  • Magnetises the blade and this collects metal filings on the blade and angle block.
  • Covers the kitchen work surface in metal filings.
  • Still requires the user to control the angle of the stone at the blade tip.
  • Easy to hit and mark the handle or other parts of the knife with the rolling stone.

Things I like

  • For most typical straight-edge kitchen knives it makes sharpening super simple and easy.
  • Elegant and attractive solution that looks good in any kitchen.
  • Choice of stone types and grits.
  • Easy touch ups.
  • Very quick to set up and use.
  • Choice of 15 DPS or 20 DPS sharpening angles.

Discussing the Review:
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