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Black Diamond says:
Our smallest, lightest and most compact fully functional headlamp that runs on AAA batteries, the Ion features a powerful, modern design for ultralight outings and emergency use.
Extremely compact and powerful, the fully redesigned Black Diamond Ion headlamp packs 100 lumens of power into a tiny package for just-in-case lighting and fast missions. With a push button housing that lets you easily switch from full power to dimmed, strobe or red night vision, the Ion has the functionality of a bigger light, with none of the extra weight.