This underwater flash kit contains all you need to set up an external strobe system for your underwater housing. This great value strobe package contains a Sea and Sea YS-03 Solis strobe head, flexible arm, single tray and fibre optic cable II M2 (optional strobe mask set may be required with non Sea & Sea housings). As the YS-03 has been designed to mimic the light intensity of the cameras own built in flash, it is not necessary to manually adjust power output. The YS-03 is compatible with any camera with pre-flash that has a TTL flash exposure function, regardless of make. The YS-03 has been designed for any underwater photographer to use and is easy to understand.