i remember getting this 15, maybe 20 years ago. it runs on a pair of 123a batteries and it goes through them like crazy. i must have tossed it in the drawer when i decided i wasn't going to feed it any more. it does throw a ton of light but it's just one brightness, you can't step it down. i know the tail cap is new. the original broke and surefire sent a new one out. but i found it and decided to add it to the flashlight arsenal. i ordered rechargeable 123a's and the base charging unit. it's solely dedicated to the 123a. i might just leave it in the truck.