ThruNite TN31 Review

Some time back, ThruNite came onto the specialty/tactical flashlight market with the super-thrower model, the Catapult. Continuing their specialty for throwers, ThruNite has released the TN31 which aims to throw a beam further than any of their earlier models. Up the front is a stainless steel bezel with some shallow crenelations. Due to the size of the head, these are obviously not meant to be used as a blunt tactical weapon, but rather just to allow light to shine through when the ThruNite TN31 has been left switched on and placed head-down. The bezel can be easily removed by simply unscrewing the it from the head if you ever need to change the lens. You can’t use the TN31 without the bezel though, because it keeps the lens in place. The ultra-clear tempered glass lens is really nicely made, its anti-reflective (AR) coating makes the lens look so clear, you might think it wasn’t even there. This should really help with optimum output as it minimizes reflected light and maximizes light output through the lens. A large and deep aluminum reflector is housed inside the head which is well finished as well. Its surface is clean and well-polished with no noticeable flaws. There are some subtle circular radiating machining lines running down the reflector, but these are really unnoticeable unless you really look for it. A Cree XM-L LED powers the TN31 and sits perfectly aligned at the bottom of the reflector cup. Alignment of the LED is really important for lights with large reflector such as the TN31 because the slightest misalignment tend to have noticeable effects on the beam profile. Externally, the head has a clean conical design with a few shallow cooling fins. A magnetic mode selection ring is placed towards the rear of the head, this controls all output modes available with the TN31. This mechanical ring has a really smooth feel when rotated and still provides tactile detents at each position of the corresponding output modes. These detents are also nicely spaced so you’re unlikely to accidentally rotate past the mode you want. One shortfall I’ve noticed is that there are no specific markings for each of the 6 constant illumination output modes the TN31 provides.

The threads between the head and battery tube are cleanly cut and mate well with each other. They also came nicely lubricated which is nice. There’s a rubber o-ring just behind the threads on the battery tube which provides a moisture seal from the elements. The entire battery tube is pretty simple and clean looking, keeping to the traditional cylindrical form factor with a generous amount of textured knurling all around. The entire body of the TN31 is finished in black Type III anodizing, as are the threads too which allows the TN31 to be locked out by simply loosening the head. The TN31 comes with a battery magazine which holds 3x 18650 batteries. The battery magazine is well-made and sturdy, it holds the batteries in place well with no complaints. Inside the battery tube, a couple of contact springs are placed at the rear end which provide electrical contact and also helps reduce battery rattle. The TN31 has a reverse-polarity protection feature built-in for safety as well. The tail cap is permanently adhered to the battery tube and is not meant to be removed. The switch used in the TN31 is of the forward push button variety which allows the TN31 to be momentarily activated by half-pressing the switch while not affective the mode selection which is completely controlled by the control ring on the head. The switching mechanism has a slightly longer than average travel, with average resistance and provides a positive tactile feel and audible click when engaged. The rubber push button switch cap is small compared to the diameter of the battery tube, however is still easy to use and activate. The switch cap sits recessed within the tail end which allows the TN31 t tail stand without problems. There are also a couple of holes at the rear end for lanyard attachments.

The ThruNite TN31 provides 6 constant illumination output levels and tactical strobe. There are accessible by rotating the magnetic control ring clock-wise (with the head facing forward) in the following order.

Level 1 > Level 2 > Level 3 > Level 4 > Level 5 > Level 6 >Stand By > Strobe

ThruNite has considerately included the Stand By position of the control ring as it allows the TN31 to be switched off without needing to reposition your hand to click the switch. The range of output provided by the TN31 is really wide, ranging from <1 to 809 lumens (tested). This range should cover all but the most demanding of use case scenarios. As the TN31 was designed to be a thrower, it comes as no surprise that the beam profile throws an intensely narrow  hot spot. The spill beam is pretty wide and covers peripheral illumination well, although it’s rather dim relative to the hot spot which would limit its practical usability as such. Overall the beam profile is clean with no noticeable flaws. The TN31 has good electronics which not only outputs a significant amount of light, but also maintains regulation really well on all output levels other than the highest Level 6 which settles around the 85% mark for most of the run time, even with active cooling. As common with most lights running on multiple li-ion batteries, output simply shuts off as the batteries run out of power at the end of the run time instead of gradually diminishing in output. As a side note, the TN31′s electronics come with a temperature control feature which protects the light from excessive heat. This essentially means that depending on the environment in which you use the TN31, it might ramp down output if there is insufficient cooling ability.

Discuss This Review Article