The Olympus UFL-3 Underwater Flash V6320120U000 is specially designed to brighten the world beneath the sea for a great underwater photography. Compact and lightweight, this underwater strobe flash is safe to use at a maximum depth of 246 feet. It features a guide number 72' at ISO 100, when used above water at full power. It connects to a compatible underwater housing using the optional fiber-optic cable. Provided with a YS style mount, it helps attaching to an optional lighting arm. Featuring TTL, slave, and 10-step manual modes, this flash is powered by 4 AA alkaline, NiMH, lithium, or oxy nickel hydroxide (Oxyride) batteries.