Package: 4PCS x Shower Door Rollers. Material: Copper + Stainless Steel + Nylon, bold copper shaft, wear-resistant, rust-free and anti-corrosion, this gives the product more durability and a longer service life. Size: 23mm diameter shower door rollers, designed to fit 4-6mm thick glass doors. 10-12mm installation aperture available. Features: Strong load-bearing capacity, ultra-quiet and stable push and pull smoothly, less effort and safe to use. Application: Suitable for most shower enclosures, shower cubicles, and steam cabins.