Installation in M16 threaded hole on the top of the housing + nut. Compatible underwater strobes: Inon Z-240/ Z-330/ S-220/ D-200, Sea&Sea YS-D1 / YS-D3 Mark II / YS-D3 DUO, Retra Pro MAX (including HSS), Marelux APOLLO III V2.0 (including HSS), Marelux APOLLO-S (including HSS).
