Belwith has lead the decorative hardware industry in design, craftsmanship and innovation since 1893. They have been bringing the very best decorative and functional hardware products to your home, with the highest quality. Brass Bit Key Mortise Lock. Brass plated faceplate. Spindle hole accommodates 1/4" to 5/16" spindle. Requires Mortise cutout. Case-hardened steel case. Replaces most bit key locks with 2-3/8 in. backset.