Seriously. Even if you do not opt for the Skylumen. The Acebeam T27 or T28 are the best 21700 throwers that meet the OP's criteria that there currently are. They frown on huge lights of a few years ago. The T27 is reasonably small and throws almost 1200 Meters. A few years ago that took about 6 batteries. I would highly suggest that you put a Samsung 40T in it for maximum performance. They come with a battery but it cannot drive it all the way. Plus these lights have a magnetic ring selector and an instant tail switch. They are HAIII. Just a splendid package. The T27 is like 150 bucks. Again, a few years ago something that could do this would have cost over a cool grand. What I like best about them is how small they are. I just did get a Vinh one and I got the top one. It is insane for such a small light but even stock it is very impressive. I highly recommend these. I would not steer you wrong. I think I have been here long enough to have a voice. Although I am by no means pushing them on anyone. I have no investment in them in any way. I will give you a very big YMMV. If you get and don't like it, please do not blame me. I am simply saying that "I" am very impressed with them. One last thing, They have plenty of spill as well so they are not bad close up either. I mean you would not use them to work inside a computer cabinet but they are good at 5 meters too. Just remember I am by no means forcing anyone to buy it! I am simply saying I personally think it is the best 21700. Now, I do not think this is as bad as flooding the thread with advertisements? It is solely my opinion. Good luck, whatever you get!