Grooved Shower Door Rollers x 4.Description: 4 wheels and 4 screws supplied. 100% brand new and high quality. Shower door rollers are internally threaded. Specifications: A - Wheel diameter: 19mm. B - Wheel thickness: 5mm. C - Protruding boss diameter: 10mm. D - Protruding boss height: 2mm. E - Hole Diameter: 4mm (M4). Materials: 304 stainless steel micro-bearing. Brass. POM. Nylon outer wheel. Stainless steel screw (M4) - will never rust.. If you still cannot find the part you are looking for or need to ask any additional questions please contact us.