http://www.ebay.ca/itm/UltraFire-UF-...item20b696af9f
I have this one on my rifle. Every connection has an O-ring so it seals out moisture, and it's fucking BRIGHT. I don't think it's a true 300 lumens, and I wouldn't recommend storing it with batteries inserted, but it still works great, and can be used as both a weapon light, and a hand light.