The e+Light uses lithium batteries, but other Petzl headlamps don't. They can't use rechargeable batteries, either--they've warned against both types causing possible fires. I do have an e+Light for summer backpacking (I don't particularly like it, but it doesn't get much use), but I use my trusty Princeton Tech the rest of the year.

Why is it so hard for Petzl to add a regulator???
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May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey