Review - Yi-Light AK21 tactical flashlight

(This product provided by the manufacturer for review.)

Today I have the pleasure of introducing a product from a brand-new manufacturer in the flashlight market; Yi-Light, and one of their first entries, the AK21.

A little about Yi-Light first.
Yi-Light is part of a larger manufacturing group that produces a variety of product categories. Originally started in 2006, the Yi-Light flashlight division is relatively new but leverages the manufacturing and engineering experience of the other divisions in the company.

So, let's get to the meat of the matter, the AK21.
We will start with the specifications as per the usual. Bear in mind that these are copied directly from the Yi-Light website and as such the English could use a little polishing.

LED: The United States imports of CREE XM-L U2

Reflector: Precision metal smooth reflector

Drive circuit: Digitally constant current circuit

Lens: Toughened ultra-clear glass lens with anti-reflective coating 

Material: Aluminum alloy

Battery: 1* 18650/2*CR123A/2*16340

Modes:  Low: 5LM /145Hrs

         Mid: 135LM/12Hrs

         Hight: 630LM/1.8Hrs

         Strobe: 630LM

Color: Military gray

Finish: Premium Type III hard-anodized anti-abrasive finish

Size: head diameter 38.3mm x body diameter24.5mm x 153mm length

Net weight: 150 grams (without battery)

Waterproof:  IPX-8

It is worth noting the range of outputs that the AK21 comes with. 5 to 630 lumens is a wide range. 

The video will cover most of the features of the light and I'll cover the rest with the following pictures. 

The AK21 is by no means a small light, but is still a very manageable size. A great light to toss in a pack or similar. 

The holster that comes with the AK21 is simple, but very serviceable. 

The tailcap is partially guarded, but does not allow for tail-standing. 

The magnetic control ring has a very smooth action, with positive detents. Very easy to use and it allows you to "pre-set" the light to a desired output before turning it on. 

The knurling is adequate without being too aggressive or slippery. It has a slight bit of micro-texturing to it which aids in grip. The tail switch itself has an impeccable action. Very smooth and positive. 

The grip provides anti-roll capability and a much improved grip on the light itself. It also has a standard tripod mount option. Very handy for area lighting uses. 

The reflector is deep and smooth, capped with an anti-reflective coated glass lens. All of which is protected by a stainless steel crenelated bezel. 

The LED is well-centered. The reflector appears to be of very high quality. 

The bezel easily unscrews, without risk of losing the lens, and provides for ready attachment of a variety of  filters. 

Battery tube is well-sized and easily accepts protected 18650 cells. 

The threads on the tailcap are square-cut and very smooth. O-ring seats are cleanly machined and should easily provide water-resistance to at least the IPX-8 standard listed. 

Gold coated spring provides corrosion resistant connection and shock absorption at the head end of the light. This prevents you from accidentally crush a battery or otherwise damage the battery via impact or recoil impulse. 

The threading on the tail-end is excellent. Extremely well-machined. 

The threads on the head end of the battery barrel are also square-cut, although not anodized. That is largely to be expected on most lights these days. 

The various parts of the AK21. Note spring inside the tail-cap. 

Here you can see some of the micro-texturing used for the knurling. 

The laser etching is excellent. Crisp, with great contrast. 

The accessory package that comes with the AK21, sans the  previously shown holster. Pretty standard package these days. Still, it is always nice to have extra switch boots and O-rings as these are generally the parts that wear out the fastest. 

High output shows no sign of PWM

Medium output is where you start seeing PWM. 

And PWM is also used to regulate the output on the lowest setting. 

Beam shot of the Ak21. Note the relatively concentrated beam. Very "throwy" for an XM-L light.  Of note, the camera pitches the hue of the light far more into the bluish than it is with the naked eye. 

As a comparison, we have here a beamshot from my other most "throwy" light, the 4Sevens Quark Turbo, using the XP-G2 LED. Despite the Quark Turbo using a smooth reflector and an LED with a much smaller die-size, the beam is clearly much wider than the AK21. 

Overall impression of the AK21 is quite favorable. Solid construction, decent to excellent machining quality and a great feature set, makes the AK21 an excellent first entry for Yi-Light. Their specifications appear to be spot on as the performance I saw during the testing period closely mimicked the numbers listed by Yi-Light. 

There are a few details I would like to see updated as far as the design goes, notably relating to the pocket clip. I mention this in the video, but the clip is just a little too long, which means that it impinges on the lip where the barrel meets the head of the light. Making the clip just a little shorter, but otherwise keeping the shape of the clip, would go a long way towards making the AK21 easier to clip to webbing, a pocket, or what have you. 

I would also recommend that the bend near the top of the clip, where it joins the ring that secures it to the barrel of the flashlight, be dropped down below the top line of the barrel ring. That would make securing the clip with the aid of the grip ring significantly smoother and the damage that occurs now would be avoided.  

This is the part of the grip ring that contacts the top part of the clip. As you can see, the part of the bend that rubs against here causes some damage to the grip ring. 

 The problem was quickly remedied by simply grinding the corners of the bend slightly with a dremel.  Lowering the bend slightly would accomplish the same thing as the modification that I undertook here. 

In essence, the only concerns I have about the AK21 are largely cosmetic and easily remedied by Yi-Lights' engineering team. Now, add in an MSRP of less than 90 dollars and we have a pretty serious contender here. Outstanding budget light option, especially considering the features and performance. Currently, Yi-Light is looking to secure dealers in the US and elsewhere. At this time, all purchase inquiries should be directed to Yi-Light.

Definitely recommended. Outstanding value for the price.