Lots of good flashlights named during this discussion. I'm not familiar with many of them but just had my wife accidentally run my Mini MagLight through the washing machine still in my pants pocket. It still works great but has lost a lot of its "character". (dirt) The light & the pants not the washer.
Having seen lots of suggestions for rechargeable lights made me wonder if he doesn't already have a light he likes, and you could be the guy to go with good rechargeable lithium ion batteries and a charger for them that fit his light? Lots of people have commented about dead batteries.
