"Zeiss Ikon Cap" (54mm inside diameter with 3 Bayonets inside) (Contarex?)
item #zeissikon54mmbayblackcap. Condition 9-. I think this cap might be for Zeiss Contarex but I am certainly not sure. The bayonet fittings will just slide over a 52mm filter but this is not how the filter is meant to mount.
