Seal extra pushbutton holes, conduit openings and knockout openings against dust, dirt, oil and water with Hoffman HOL-SEALERS#153;. Seals will cover any size or shape of hole from .19-in. diameter to maximum diameter shown in table. Can be used on enclosure walls up to .31-in. (8-mm) thick. Steel Models, 16 gauge galvanized steel backplate, Plated stud (10-32x5/8) and wing nut, Stainless Steel Models, 16 gauge stainless steel backplate, Seal, backplate, stud (10-24x5/8) and wing nut are 300 series stainless steel.