System series standard battery model buoyancy adjustment float.
By fixing with the attached fixed plate, the underwater weight becomes neutral buoyancy, reducing the burden when shooting underwater. Fix it with the attached fittings and bolts to attach a ball adapter, a YS adapter set, a quick shoe adapter, etc.
Compatible products: System 01, 02, 01-SB
(Standard battery: BM3100G, BM3400B, 3500B)
* System01/02: RE series (standard battery: BM3521S) cannot be attached.