【Package】: 4PCS x Shower Door Rollers. 【Material】: Copper + stainless steel + nylon, bold copper rod, wear-resistant, rust-free and anti-corrosion, which makes the product more durable and has a longer service life. 【Size】: 23mm diameter shower door rollers, designed to fit 4-6mm thick glass doors. 15-17mm installation aperture available. 【Features】: Strong carrying capacity. load-bearing, ultra-quiet and stable push and pull smoothly, less effort and safe to use. 【Application】: Suitable for most shower cubicles, shower enclosures and steam cabins.