My brother bought two of these. ONe for his girl friend and one for himself. They really like them. I'm not sure what LED they use. They are not very bright. They use 4 button cell batteries.
Believe it's a 5mm Nichia CS. Those batt's won't last long tho and it's probably closer to 5-7 lumen.....................and not for very long at that. I'd recommend stepping up a bit to the Microstream (also by Streamlight)