Package Content: Set of 4 Twin Shower Door Rollers (2 Piece Top & 2 Piece Bottom). Galvanized door rollers: Double rollers for shower door up and down 23 mm (diameter), plated surface, anti-rust; Suitable for 4-6mm glass door thickness, 13.5-14mm glass open hole. These Replacement Shower Door Wheel are suitable for most shower stalls, shower stalls and steam stalls, installed at the top and bottom of the shower door, for easy opening and closing. / li> No noise to open the shower door and these glass shower door rollers help it slide smoothly. It is easy to install and maintain.