The MK.II R has a very clean designed head, the coating on the exterior of the head is nice, smooth and consistent. The coating is a gray with a slightly brown hue. Aside from the branding printed on the bottom area of the head’s exterior, there aren’t any other aesthetic touches on the head. The MK.II R is advertised as using a sapphire crystal lens, as with all JETBeam products. An orange rubber o-ring sits between the lens and reflector which provides a good seal as long as the emitter module is screwed in securely. The reflector and emitter are very well-aligned with each other, the reflector is slightly deeper than other lights of similar. The emitter module isn’t adhered or permanently attached to the head in any way so you are able to easily unscrew it from the rear of the head. The “+” contact has a gold coated spring soldered to the PCB which means that flat topped 14500 cells can be used without problems. Threads on the head are of medium thickness, not too fine and well-machined. They don’t cause any grinding or squeaking when being screwed onto the battery tube.

The battery tube has the same consistent and well-finish coating as the head. Color of the coating is also well matched with that of the head. There are 3 flat faces, and 3 horizontal slots machined along the length of the battery tube. The flat faces give adequate grip and the horizontal slots are deep enough to small tritium vials in if you want. The walls of the battery tube are quite thick, so it shouldn’t be easily dented or damaged. Protected 14500 cells will fit without problems. Threads on either end of the battery tube are well-machined as well, medium thickness and well-cut. I did not experience any grinding or squeaking while screwing on the head of tail cap. There are also 2 orange rubber o-ring on either end of the battery tube, just before the threads. I find them slightly too thick though, screwing on the tail cap you’ll experience that it’s noticeably more resistance than other lights such as the Fenix lights. Then again, a good thing about this is that the seal provided by these o-rings are that much more secure. There’s a band of knurling about 0.8cm wide around the tail cap which provides good grip when unscrewing during battery changes. You can attach lanyard attachments to either of the 2 rectangular slots machined at the end of the tail cap. The MK.II R comes with a bright yellow push button cap pre-installed which can be changed to the slightly more subdued orange one also included in the package. Inside the tail cap is a regular reverse push button switch, so momentary activation isn't possible. The switching mechanism has short travel and tension is above average, while not being too hard to press. The push button switch cap is recessed within the tail cap and allow the MK.II R to tail stand on flat surfaces easily. One thing to take note about screwing on the tail cap after inserting a battery in the MK.II R is that they can be quite a tight fit due to the springs on both the “+” and “-“ contacts.

The MK.II R uses a Q4 bin Cree XR-E emitter, and output from it is pretty decent. However on 100% brightness, runtime does suffer as can be seen from the graphs below. The regulation circuit in the MK.II R seems to have a peculiar behavior as input voltage decreases from a li-ion cell where output noticeably increases towards the end of the battery life. Overall beam profile is nice and smooth thanks to its textured reflector, there is still the characteristic dark ring around the hot spot which is common in XR-E based lights. Color temperature of the light produced is slightly on the warm side.

The user interface of the MK.II R is separated into 2 modes, Daily and Advanced Mode. Changing of levels and strobes within these modes are done via the familiar half-presses. The electronics also has a memory feature, but only for the Daily Mode. This means the light will remember the last level used and switches on to that level the next time it's turned on. In Advanced Mode, the light always comes on at 100% when first switched on. Also, I noticed that on lower output levels, the MK.II R produces a constant, subtle high frequency sound.

Operating modes are as follows:

Daily Mode
100% > 5% > Strobe (12 Hz)

Advanced Mode
100% > Strobe (15 Hz) > 10% > 20% > 30% > 40% > 50% > 60% > 70% > 80% > 90% > Strobe (5 Hz) > SOS (100%) > SOS(5%) > Standby Mode (Flashes once every 6 seconds at 5% brightness)

The Good - Option for Daily and Advanced Modes gives flexibility for users who want simplicity or more detailed interface. Good build quality, all parts fit together nice and snug.

The Bad - Runtime performance is below average. Expected to be brighter since it's advertised as having a Q4 bin XR-E LED.

The Relative - Odd color choices for rubber switch caps. Beam has a slightly warm color temperature. Uses a reverse push button switch. Emits a high frequency sound on lower output levels.

Head (front view).

Head (side view).

Head (rear view).

Battery tube (front view).

Battery tube (side view).

Battery tube (rear view).

Tail cap (front view).

Tail cap (side view).

Tail cap (rear view).