Configured like its counterpart, the popular YS-90TTL Duo strobe, the YS-90DX is compact and lightweight, constructed of high-impact polycarbonate. It bears the same prism diffuser, projecting an ultra-wide, even beam. But the YS-90DX goes beyond dual system capability; it is the world's first submersible flash to have intuitive circuitry with triple-system compatibility. A traditional four-pin sync cord synchronizes it with the Motor Marine II-EX. A traditional five-pin sync cord synchronizes it with Nikonos and housed Nikon systems. And the Sea & Sea fiber optic cable synchronizes it with digital still cameras.When used with a traditional sync cord, the YS-90DX operates in TTL automatic, slave and manual modes. When used with digital cameras via an accessory fiber optic cable, the YS-90DX is slave-fired. The YS-90DX responds when the camera's built-in flash is fired. Some digital cameras have a pre-flash to measure subject distance and available light, some fire only once. The YS-90DX can be set to fire when you want it to. It operates in manual mode only. Total manual flash exposure is achieved by means of the strobe's unique 12-option light level control dial. The YS-90DX, a futuristic strobe for today's underwater imagers.