Max output 1000 lumens. Max beam distance: 162m. Max runtime: 330 h. CREE XM-L2 U2 LED with SMO reflector. Instant turbo output enhances flexibility and practicality. Integrated precision digital optics technology provides extreme reflector performance. Five rapidly switchable brightness levels and three concealed special modes: location beacon, SOS, strobe. Full metal, super compact construction. Uses 1-18650 battery or 2 CR123 batteries (not included). Breathable nylon headband. Length: 3.86" with 0.95" head size. Water and impact resistant. Hang packaged.