HSS Optoelectronical TTL-circut for Isotta housings, compatible with all Nikon DSLR cameras. Compatible underwater strobes: Inon Z-330 / Z-240, Retra PRO, Sea&Sea YS-D1 / YS-D2 (China) / YS-250, Ikelite DS161 / DS160, Subtronic Pro-270 / Pro-160. Product supports Retra HSS up to 1/8000.