The more I think about it while typing this post, I guess it's pretty common for flashlights to have 20 to 1 threading, especially the ones that take 18650 batteries. I was tinkering around like we all do from time to time and screwed on one of my top caps on to my flashlight light and what do you know, a perfect fit. Fires up and everything. It's actually my shortest 18650 mod now. The light top screws directly onto the mod as well. I guess it was just kinda exciting at first to realize I had another mod and I didn't even know it. I believe I paid around $10 for this light and to be honest I actually like the grip, the button switch , and the look of it more than some of my other cheap mods. I always keep this in my glovebox and it's nice to know now that I have a backup mod just an arms length away. I need to hunt down a cheap top cap to throw in the glove box with it. I'm sure this is nothing new to most of you but just thought I'd throw it out there. Ultrafire LY-501B 20*1 threading, tested with Pegasus and Gus Lord.