[Heavy Duty Construction]: This courtyard sliding door wheel has a heavy-duty structure and is very sturdy and wear-resistant. It adopts high-quality double steel ball bearing wheels, which can work smoothly and silently during sliding door movement, ensuring smooth opening and closing of the door. Commonly used to replace rollers on wood, extruded aluminum or vinyl sliding patio doors manufactured by Weathershield, , Malta, Pozzi, Hurd, Peachtree, Jeld , Caradco and others. [Standard Size] The roller assembly contains 5/16-inch wheel thickness (width) x 1-1/4-inch diameter, 5-3/4-inch hole centers. This roller assembly has a minimum collapsed height of 1-1/2 in. [Solid Construction]High quality radial still working after 100,000 cycles for 2 rollers bear 120KG. While others may use the bearings made from Carbon Steel W/O heat treating, we insists all bearings made from Heat Treated Bearing Steel [Easy to Install]Remove damaged or missing roller assemblies in patio sliding glass doors , then install new sliding door roller assembly. Material: Metal colour: As shown Package Contents: 2 x Heavy-Duty Sliding Door Rollers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.