Sizes Available Medium: 1.18" Diameter - Threaded rod M4 Large: 2" Diameter - Threaded rod M5 The glass door knobs are supplied with two knobs (front and back), threaded rod, and gasket for back to back mounting. Fits glass up to 8 mm (1/4"). Please contact us if you need a to install on thicker glass as a longer rod can be provided.