Easy Activation: Simple head twist to active with 90 lumens with machining for optimal grip. AAA Battery: Powered by a single widely available AAA battery. Incredible Performance: Features a high-performance Philips LUXEON TX LED and a PMMA TIR lens that focuses the light to reach out up to 44 meters. Mini Size: As small as your pinky finger, weighing in only 0.68 oz, measuring in 2.38 in.