Material: Plastic, BS nylon and stainless steel shower door rollers. Colour: Gray Shower Door Rollers; Pattern: double shower door rollers. Castor diameter: 23mm; Width: 5mm. Minimum hole size in glass: 11mm. Suitable for glass thicknesses of sliding doors from 3 to 6 mm. These single shower door rollers fit glass shower doors where the distance between the center of the hole and the edge of the glass is 18mm. The package includes: 4 shower door rollers top + 4 shower door rollers bottom