CRL Cylinder Style Brushed Nickel Finish Back-to-Back Shower Door Knob Back-to-Back Knob Without Protective Plastic Sleeve Fits 1/4&quot; to 1/2&quot; (6 to 12 mm) Thick Glass Solid Brass Material Use Monolithic Tempered Glass Requires a 3/8&quot; to 1/2&quot; (10 to 12 mm) Hole