I got a JKK03, my first impression is that it is small, smaller what I expect for a 3x 18650 light. The length of it is about the same as a Convoy S2+. I bought the XHP50.2 6500K version as it is the cheapest and I’m gonna swap the emitter anyway. It has 3 modes, triple click (IIRC) to access turbo and quadruple click to access strobe and SOS. One thing that is bothering me is the mode order, being High - Mid - Low which I don’t prefer. The cooling is pretty good thanks to it’s unibody construction. I did not use the light too much before I replaced the XHP50.2 with a Nichia 144A, but the yellow corona is very noticeable even when cycling on a grey road. I guess pairing s large SMO reflector with a XHP50.2 is not a wise decision. The light uses a boost driver and the XHP50.2 is in 6V setup. The heat in high mode is acceptable and it can stay in turbo for quite a while before getting too hot to hold. However I don’t think it has any turbo timer/ temperature regulation so one has to be careful when leaving it on turbo. With the 144A, the beam pattern is also horrible, perfectly showing the egg yolk in the hotspot and a yellowish ring in the corona-spill area. I’ll post some photo of the driver and light if I have time soon.