This Patio Screen Door Spring Tension Roller features a 1/8 inch (3.2 millimeter) O.D. by 5/16 inch (7.9 millimeter) tall locator pin which holds the roller in a fixed position. The 1/4 inch (6.4 millimeter) wide nylon wheel has a center groove. This sliding patio screen door roller is used by several patio door manufacturers.