I just saw on their webpage terraluxcorp.com how they came out with their newest lighthead. It is supposed to produce a whopping 600 lumens, which is greater than a 50 W MR-16. It's designed to be stuck into the head of a 4-6 D cell Maglite. I seem to remember someone who built a bike headlight with a Maglite head. This new head sells for around $100 last time I checked. Any MTB people want to venture a guess as to how useful this light would be (600 lumens is way too much for on-road commuters).