Streamlight 61304 ProTac HL Headlamp - 635 Lumens Powered by 2 3-Volt CR123A lithium batteries with a shelf life of 10-years 540-Lumens of blinding light reaches 172-meters LED Solid State Power Regulation provides maximum light output throughout battery life Packaged with an elastic headband and a rubber headband for helmet mounting Serialized for positive identification