ALPA backadapter CO645A - for the Contax 645 interface, adjustable with shim kit, max. +/- 3/10 mm in steps down to 1/100 mm, for digital backs only.
ALPA introduced adjustable adapters for digital backs at Photokina 2004. Since then, ALPA adjustable adapters are shimable in a range of 1/100 mm to 3/10 mm. Each such adapter is provided with the respective shims.