PETZL TRIOS helmet size 2 White E54AW2 EASY TO CHARGE: Compatible with Micro USB port. VERSITILE: Can be used at high and low temperature. KEEP YOUR LIGHT GOING: Use as a main power source or backup power. KNOW HOW MUCH POWER YOUR HAVE: Features indicator light for remaining burn time. COMPATITIBLE WITH: REACTIK, and REACTIK+ Headlamps.