I also carry a Petzl e+Lite in my bag at all times. Picked up two at the local Eddie Bauer when they had them on deep discount. (May have been a going out of business sale, can't remember.) Unless you buy online, the coin cells are pretty expensive, but they have a great shelf life and the little Petzl has an excellent switch system which makes it nearly impossible for it to accidentally turn on in the capsule.