Chrome Plated, Back to Back Cylinder Style Shower Door Knobs with plastic cushion. The thin clear plastic sleeve on the interior knob is ideal for use on sliding bypass shower doors to protect the knob and glass surfaces. Knobs measures 3/4" in diameter and stand 1-1/4" from the door surfaces. Solid Brass construction. These shower door knobs include clear plastic handle end washers as well as an interior plastic washers to protect glass against metal contact. Accommodates 1/4" to 1/2" glass. Requires a 3/8" to 1/2" diameter hole for installation.