This URSA Mini Pro Shim Kit from Blackmagic Design includes nine shims and a baffle tool. The kit permits you to adjust the flange focal distance of your mount to meet the tolerances required for maximum lens performance. This kit is useful with the URSA Mini Pro and URSA Mini PL.
These precision-cut shims allow the mount to pass electronic information from the camera to the lens mount, and it can be used with any of the replaceable lens mounts for the URSA Mini Pro.