The camera should be PL Mount. This adapter is for converting the old Arri Bayonet lens on Arri PL Mount.
High quality CNC machined and precison ground brass contruction
The adapter comes with 5mm screws for tightening it to the lens without any pressure on the lens focus inner cylinder
May also be attached to old bayonet lens by the 6 holes drilled around it (with flat head screws NOT included)
PL means "positive lock," the successor mount to the Arri Bayonet
The PL adapters were made especially for Illumina lenses but can work for other old bayonet mount lenses. The idea is to find excellent old lenses, which are on the market for a good price, and adapt them for modern use.