For decades Omega supplied aluminum thumbscrews for mounting lens discs and lens plates on a number of Omega enlargers with interchangeable lens boards, including the D5, D6, C-67, B-66, B-22, etc. In situations where lenses are changed frequently some users may find that the aluminum screws may wear or break frequently. For those circumstances we can supply this stainless steel version of the same thumbscrew. The screws are new, sold in pairs.