Underwater strobes (or flash) lights are the key to capturing bright colours underwater, that are otherwise subdued due to the effect of water. The majority of today's strobe lights are synchronized via a fibre optic cable from the camera's on-board flash. As the name suggests, an underwater flash gives out a bright and brief burst of light that can be controlled both automatically and manually. Underwater strobes come in various sizes and power levels that you can choose from. The two main manufacturers of underwater strobe lights are Inon and Sea & Sea.