The Photon II PRO Key Light lasts up to 18 hours, emitting 4.5 lumens of light from its tiny body. The tough, water-resistant case has an IPX-7 waterproofing ready and is intended for heavy and extreme use. The LED micro-light for adventurers and hard-workers, the LRI Photon II PRO key-chain light stands up to any challenge with consistent lighting. With an easily replaceable battery, this LED key-chain micro-light is a must have accessory.