Tag Archives: Keychain

Wurkkos COB Keychain SQ05

  1. Introduction
  2. Manufacturer Specifications
  3. Package Details
  4. Build
  5. User Interface
  6. Circuit Measures
  7. Emitter Measures
  8. Beamshots
  9. Testing Results
  10. Runtimes
  11. Pros and Cons
  12. Overall Rating
  13. Preliminary Conclusions
  14. Acknowledgement


This is a slightly shorter “mini-review” of an inexpensive keychain style light, the Wurkkos COB SQ05 flashlight. Or, as it is likely better known – the free gift when you spend between $49 and $99 USD in the their online store. But you can actually buy this is as a standard alone item for ~$6 USD or so, with standard store discounts.

I won’t be providing quite as much commentary as usual (and beamshots will definitely be out), but otherwise will provide my full suite of testing results so that you can make informed decisions around output, use and performance.

Obviously, I’m not expecting much from the simple COB LED emitters on this keychain light – although I am impressed to see a built-in rechargeable battery with standard USB-C charging port. Let’s see how it performs in my testing.

Manufacturer Specifications

Note: as always, these are simply what the manufacturer provides – scroll down to see my actual testing results.

ModelKeychain SQ05
Emitter30x COB wicks
TintCool white
Max Output (Lumens)500
Min Output (Lumens)150
Max Runtime4 hours
Max Beam Intensity (cd)-
Max Beam Distance (m)-
Constant Levels-
Weight (w/o battery)-
Weight (with battery)50 g
Length95 mm
Head Diameter55 mm
Body Diameter27 mm

Package Details

The light ships in a colourful but thin cardboard box. As you can see, mine got dented during shipping, but it didn’t affect the light. Inside, you will find the following:

  • Keychain light, inside a small bubble-wrap pouch
  • Short USB-C charging cable
  • Simple manual

It’s a very basic package, in keeping with the budget price. But I am still surprised/impressed to see the USB-C charging port and cable included.


From left to right: AAA NiMH, AA NiMH, Wurkkos Keychain SQ05, Armytek Crystal.

Note that the last picture above is when the battery is nearly exhausted, and the light is producing very low output.

Build is fairly basic, all-plastic in design, but better than expected for the price.

You have a simple carabiner-style clip that opens inward to allow you to attach it to a keychain, bag, or purse. There’s a button on one side that covers the electronic switch, which has a somewhat “soft” feel. On the opposite side is the USB-C port under a flimsy cover (attached but loosely fitting, I wouldn’t consider this very waterproof). On the bottom is a tripod mount, and on the top right corner is a “bottle opener” feature.

The light has a magnet on the back, allowing you to affix it to metal surfaces as a worklight. It also has a very simply plastic stand that opens up from the back, and that allows you to angle the light on flat surface (I found this plastic stand to be very flimsy, and it feels like it could break easily).

The main part of the light is the giant yellow phosphor square with 30 COB light wicks, arranged in a 5×6 grid. COB stands for “Chip-On-Board”, where the LED chip is in actual direct contact with the substrate. This allows COB makers to make large arrays, and potentially pack in the emitters more densely than with traditional discrete designs. This is not common for flashlights though, where some degree of throw is generally desired (and thus requires smaller emitters). But it can be valuable when you are looking to produce wide and even flood patterns.

Again, this is better quality than I expected for ~$6 USD (or less) keychain light.

User Interface

The manual is pretty simple, more a description of the features than an actual set of instructions. Here is a rundown from my testing:

From Off:

  • Single-click the switch: Turns On in 60% output.
  • Press-and-hold the switch: Turns On in 100%

From On:

  • Single-click the switch: If in 60% mode, advances to 30% output.
  • Single-click the switch again: If in 30% mode, advances to strobe.
  • Single-click the switch again: If in strobe, turns Off.
  • Press-and-hold the switch: Jumps to 100% (note that a single click of the switch again when in 100% mode turns Off).

And that’s it. So, in the main sequence you have to pass through 30% and strobe in order to turn Off through repeated clicks (ugh). This is not a good interface. However, if you do a press-and-hold to jump to 100% at any point, a single click will now turn you off.


Yes, a press-and-hold jumps you to 100% at any time.

Mode memory:


Strobe/Blinking modes:

Yes, there is one high-frequency strobe.

Low voltage warning:


Lock-out mode:


Reviewer Comments:

This is about as basic as you could imagine an interface being. I really don’t like having to cycle through strobe to turn off in the main sequence, but at least you can bypass by going to 100% first.

Circuit Measures

Pulse-Width Modulation (PWM):




The light is actually controlled by PWM at the reduced 30%/60% output levels, as you might guess from the oscilloscope traces above. To confirm, here’s an expanded scale on the 60% output level, where you can see the classic square sine wave pattern of PWM:


At least the PWM on 30%/60% is at a decently high 3.9 KHz frequency. This is not particularly noticeable in practice, even to someone sensitive to PWM. Indeed, you won’t easily detect it unless you shine it at a fan or running water.


There is a single strobe of 8 Hz frequency (which is higher than I would like for a keychain light – this isn’t some sort of tactical device, after all). As you can see from the trace above, the PWM is visible during the on-phase of the strobe. This is because the strobe is running at reduced power (I believe it is the 30% output level).


The initial charging current is ~0.45A, when the battery is nearly fully depleted (i.e., just a very low output from the emitters). As the light charges, the charging current quickly drops (i.e., to ~0.40A within a minute or so, keeps dropping from there). It doesn’t take very long to fully charge the light (I didn’t time it, but it is under an hour).

Standby / Parasitic Drain:

Given the electronic nature of the switch, there must be a standby current at all times. However, without breaking it open, and I am not able to measure it.

Emitter Measures

In this section, I directly measure key emitter characteristics of my sample in terms of colour temperature, tint, and colour rendition. Please see my Emitter Measures page to learn more about what these terms mean, and how I am measuring them. As tint in particular can shift across levels, I typically stick with the highest stably regulated level for all my reported measures.

As explained on that page, since I am using an inexpensive uncalibrated device, you can only make relative comparisons across my reviews (i.e., don’t take these numbers as absolutely accurate values, but as relatively consistent across lights in my testing).

60% Level:

The key measures above are the colour temperature of ~5930K, and a slightly positive tint shift (+0.0113 Duv) to yellowy-green at this temperature. For CRI (Ra), I measured a combined score of 71.

These values are very consistent with budget cool white emitters, and match my visual experience of this light. It’s actually better than I expected for the price.


Sorry, no outdoor beamshots for keychain lights. 🙂

Testing Results

My summary tables are generally reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. In addition to the links above, please see my output measures page for more background.

All my output numbers are based on my home-made lightbox setup. As explained on that methodology page, I have devised a method for converting my lightbox relative output values to estimated lumens. My Peak Intensity/Beam Distance are directly measured with a NIST-certified Extech EA31 lightmeter.

SQ05 Testing Results

ModeSpec LumensEstimated Lumens @0secEstimated Lumens @30 secsBeam Intensity @0secBeam Intensity @30secsBeam Distance @30secsPWM/Strobe FreqNoise FreqCharging Current <3VCharging Current >3VParasitic DrainWeight w/o BatteryWeight with BatteryCCT (K)DuvCRI
30%1506055---3,916 HzNo0.45 A0.40 A--34 g---
60%300105100---3,916 HzNo0.45 A0.40 A--34 g5,9300.011371
100%500170160---3,916 HzNo0.45 A0.40 A--34 g---
Strobe------8 HzNo0.45 A0.40 A--34 g---

Output is lot lower than the rated specs (not entirely surprising). While I don’t doubt you could build a 500-lumen COB emitter array this size, this example seems to be lower density (and driven lower).

To view and download full testing results for all modern lights in my testing, check out my Database page.


As always, my runtimes are done under a small cooling fan, for safety and consistency. To learn more about how to interpret runtime graphs, see my runtimes methodology page.

First thing you will notice is that all three output levels quickly step-down to much lower outputs, and then maintain a fairly stable flat runtime. Note as well that maximum output – even at initial activation – is lot lower than the rated specs (although the relative 30/60/100% distribution seems accurate, scroll down the measurement table for detail).

The light doesn’t actually turn off during the runtimes above, it just drops to a super-low level. I suppose it will eventually fully drain and shut off, but I don’t recommend you let it drain down that far (i.e., over-discharge is not good for rechargeable cells).

Here is a blow-up of the first few minutes, so that you can see the drop-down over time in better detail:

This is clearly a programmed step-down pattern. Both 100% and 60% begin their straight-line step-down at exactly 1 min, whereas the 30% level does it at exactly 1.5 mins. 100% takes 2.5 mins to step-down, 60% takes 1.5 mins, and 30% takes 1 min exactly.

I appreciate the stable runtime patterns, and flat regulation. But my subjective impression is that output/runtime performance is quite low for a “500mAh” rated battery (making me think that this spec is similarly over-stated).

To put these results in contact, here is how it compares to a more expensive competing dual white/red emitter keychain/headlamp model from Armytek that I will be reviewing next (rated at 600mAh capacity):

Pros and Cons

Decent build quality and feature set for the incredibly low price.Initial output is far below rated specs on all levels, and rapidly drops down to considerably lower output.
Good regulation pattern, with programmed step-down and flat stabilization (although output is much lower than reported).Lower output levels are controlled by pulse-width modulation (PWM), although at a reasonable 3.9 kHz.
Very even flood beam without artifacts, at a standard cool white temperature.Runtimes are much lower than I expected for the rated battery capacity.
Standard USB-C charging (cable included) - but battery seems lower capacity than rated.User interface is very basic, with strobe on the main sequence.
Integrated rechargeable Li-ion is not user replaceable.
A bit large for a keychain light.

Overall Rating

Preliminary Conclusions

This is actually a very decent little budget keychain light. For ~$6 USD (or less, as it is thrown in for free with a minimum $49 purchase from Wurkkos), it is a great buy. I was pleasantly surprised to see the feature set at this price point – cool white beam, very even flood, multiple levels, stable regulation, and rechargeable by USB-C. Wow!

Clearly, we have come a long way from those awful little coin cell-based 5mm LED squeeze lights that used to come for free with flashlight purchases. I vividly recall their bluish beams, horrible beam artifacts, rapid direct-drive drop-downs, etc., etc.

So, why the low star rating here? Well, I’m not including price in my rating system, but instead focus on objective results. In that regard, this light is disappointing relative to rated specs. Initial output is very far below quoted specs (i.e., at best no more than a third as bright as the rated “500 lumen” spec in my lightbox). And actual output then quickly drops down ~70-80% from those initial low levels for the extended runs. Finally, actual runtimes are much shorter than I would have expected for the rated battery capacity.

The user interface is also pretty basic – it’s been at least a decade since I saw a light where you had to cycle through a high-frequency strobe to turn it off. The rating would have dropped further if it weren’t for the work-around option to go through 100% before clicking off instead!

Similarly, this is the first time I’ve seen PWM since my return to reviewing – although thankfully at a reasonable ~4 kHz frequency. If it weren’t for the programmed step-down patterns, I would think this was actually a circuit from 10-15 years ago.

But all that said, this still seems like an outstanding value as a (nearly) free item. I plan to slip mine into my travel backpack, as an emergency backup light. My only concern is that I don’t know what the standby drain is like, and would be worried about starting a charge cycle if it gets over-discharged (i.e., the fire risk/safety of inexpensive built-in Li-ions is always unknown). But it does seem like a good solution for anyone looking for a simple back-up light with a great flood beam. Just match your expectations to the price – you get more than you pay for here, but only up to a point.


The SQ05 was included as a standard free gift in an order I made through the Wurkkos website. As always, all opinions are my own and the light received the same rigourous and objective testing as all other lights that I have reviewed. At the time of review, this light retails for ~$6 USD (~$8 CDN) or less with coupons, and is included for free on orders >$49 USD.