The Sea & Sea YS-250PRO is designed for demanding professionals. The strobe is packed with features to meet the challenges of digital photography in the underwater environment. The strobe features a large circular arc tube that emits a powerful flash at guide number 32 (its value on land / ISO 100 / m) when power is set to full. The strobe provides incremental manual flash power adjustment in 12 steps for fine adjustment of light. It also works in TTL mode for camera-adjusted light levels.
The YS-250PRO is lightning fast: it recycles in one second. The high-capacity Ni-MH battery is designed exclusively for the strobe. It stores enough power when fully charged for 300 full flashes. The strobe also features a high-luminosity white LED target light in the center of the strobe. This shows precisely where the strobe is pointed. There is also a ready lamp and TTL lamp on each side of the strobe to indicate when the strobe is charged and when it is being controlled by the camera's TTL. An audible signal sounds when the ready lamp lights, so you can concentrate on your subject in the viewfinder and know precisely when the strobe is ready to fire again.
The YS-250PRO includes other sophisticated features such as two fiber-optic cable sockets and pre-flash cancellation that handles up to two pre-flashes from the camera. Slave mode allows the strobe to be used in cordless dual-strobe or multi-strobe photography. With all of these features the YS-250PRO is at home in the water both day and night. The strobe will help you create the best possible underwater images.