This TTL Underwater Housing from Ikelite is a waterproof case enabling you to shoot beneath the surface with your Canon PowerShot G16 digital camera. It has a depth rating of 200'. Mechanical controls provide access to all camera functions except for the diopter adjustment dial. The camera's built-in flash is also usable.Built for durability, the housing is constructed by hand in the USA from corrosion-resistant polycarbonate, which is clear to allow you to monitor the o-ring seal and maintain a full view of the camera. The housing's built-in, flat glass port accommodates the camera's lens, and also accepts optional, external wide-angle and macro add-on lenses.Expand your system by adding an optional Ikelite DS Substrobe. The housing's built-in circuitry and 5-pin electrical bulkhead enable TTL exposure with these TTL-compatible strobes, which are triggered without requiring your camera's built-in flash to fire. Non-Ikelite strobes are available, too, though these will provide manual exposure only. The included aluminum tray with left-hand rubberized grip provides a quick-release point for your external strobe, while also improving balance and handling underwater.