Nebo's einstein 1000 is a compact 1,000 lumen low profile headlight with 5 lighting modes with flexible power. use the included rechargeable battery or 2 cr123a batteries. turbo modes (1,000 lumens): 10 second intervals / 120 meters high (350 lumens): 3 hours / 55 meters medium (150 lumens): 6 hours / 50 meters low (10 lumens): 18 hours / 14 meters red (5 lumens): 12 hours / 1 meters *run time is reduced by approximately 20% when 2 cr123a batteries are used