Review: Fenix - TK-51 light

I had the good fortune to be introduced to Braent Hong,
Asia Pacific Sales Manager for Fenixlight Limited at the SSAA SHOT Expo by my friends at LEGear Australia and made an impression about my love of all things lighting.

He recommended I contact their marketing department, and sign up to be a beta-tester, and after many month of negotiations, I received this pre-release TK-51 model light. This is a BIG light, and it certainly performs.Here it is stacked against the HexBright crowd-funded light, I have covered previously.

Let me tell you about the TK-51 ....
At 18.8cm (7.4") long and having a grip diameter of 4.8 cm (1.9"), and weighing 430g without the batteries, this is quite a serious hand held light. At the buisness end, it features two  Cree XM-L 2 (U2) LED's, in a tear-drop configuration of reflectors.

The body of the light is made of machined aircraft alumiunium, Type III hard-anodized and features a toughened and anti-reflective coated glass facing. The two Cree LED's sit in differing reflectors, one large and deep, the other quite shallow. Both reflectors were mirror finished. The glass was in-set from a smooth lip.

The tail-cap was crenelated, and two of the opposing crenelations feature a strap hole for securing a lanyard. The tail cap unscrews to expose the battery holder, which is well labeled to ensure that not only the battery holder, but the batteries themselves are properly loaded, avoiding any misloads.

Speaking of batteries, it is designed to take three 3.7V Li-ion 18650 batteries, which for those who don't know are the big-brother of the CR-123A batteries becoming so prevalent in the resilient gear market. It will also take six of the CR123A's in place of the 18650's, and even the 3.2V 16340. In the absence of a full load, it will even operate with one or two batteries alone, but at much reduced performance.


the TK-51 has some interesting controls, with individual controls for the spot and flood LED's, which ramp up from Low, to Medium, Medium-high and High modes, each accessible by a tap of the appropriate control. It also features a memory, such that the on/off button will recall the previous settings for both LED's. Momentary Strobe can be produced at any time by holding either LED controller, and cycles between two distinct flash frequencies. Momentary "TURBO" mode is achieved by depressing the on/off button, and gives full power to both LED's. Which is a LOT.

Each LED has a Lumen output of 10, 150, 400 and 900. This effectively ramps up with a button press for each LED control, offering considerable control of light output for the user, given their need. with a Single LED runtime, running from 420h at Low for a single LED, to 1h 45min for both LED on high, there is also considerable operational variety. I found that the buttons were perhaps -too- easy to press, being raised from the surface, and had a very light pressure needed to activate.

Fenix state the beam distance is effective to 425m, with a peak beam intensity of 45200 cd. Put simply, it packs a whole lot of light, and can throw it a long way.

This shot is of the TK-51 with both LED's at high, in TURBO mode, putting out 1800 lumen, and lighting up my whole street. I angled the spot down, so as not to side-blind passing cars at the end of the road.

Low Flood

Low Spot

The low flood and spot were hard to catch on my iPhone 5s, but the reflective paint of my old car glinted well enough, remember, this is 10 lumen

Medium Flood

Medium Spot

The medium options, at 150 lumen match most over the counter service station and supermarket lights that I've had. My trusty "household blackout light", the 5.11 ATAC-A1 is only 103 lumen (but off a single AA) .

Medium High Flood

Medium High Spot

At Medium High, the TK-51 is putting out 400 lumen from each LED, doubling that of my CR123A powered Surefire 6pX.

High Flood

High Spot

At High, the LED's are outputting 900 lumen, which even outstrips my HexBright FLEX, and is just shy of my new car headlights. On top of that, the built in circuitry has both output lock-out, meaning that it will produce the same light output for as long as the charge allows, then drop to the next level, and so on, rather than dimming gradually. At the lowest power levels, the light will blink its LED's three times as a last-ditch indicator of power loss. There is also overheat protection, which down-shifts the output until the light cools. During my use if the light, the finely machined texture on the grip was good in the hand, and the light had surprisingly good balance. I hate to think what it would feel like wielded in anger.

Combined with the mass of the light, its 1m shock resistance, and IPX-8 (2m) water resistance, this is a serious light, for serious use. I bought rechargeable batteries for it, and a charger, which comes wit ha car-adapter, which I think will greatly expand the use I get from this light. Now to find a pouch for it!