The Photon II PRO is an extremely durable LED key chain flashlight with an ultra tough, water-resistant case. This LED micro-light delivers 4.5 lumens of light, and is visible up to a mile away. Powered by a lithium battery, the Photon II PRO LED key light lasts up to 18 hours. The battery is easily replaceable, making the PRO a powerful LED micro-light that will last you for many years.