Divelights are specially designed for underwater sports practiced by recreational, technical and commercial divers as well as dive photographers and videographers. These devices must be watertight under pressure and corrosion resistant to withstand the harsh underwater environment. The beam spread of a diving light, be it a tight beam or a wide flood, depends on the kind of diving activities. A tight beam with little spill light help see down caves and crevaces, or into wrecks. It also provides better visibility in murky water.