It is a multi-function ARRI Rosette(M6, 31.8mm diameter) Mount.
There are two 1/4''-20 threaded holes and two #8-32 threaded holes on this rosette mount. When used with the Zacuto VCT plate, it can be attched to both the side(with the 1/4''-20 threaded holes) and the front area(with the #8-32 threaded holes). Where to mount the rosette is based on your needs.
2x 1/4" Screws
2x #8-32 Screws
2x Hex Spanner
Material: Aluminum Alloy, Stainless Steel
Net Weight: 40g