[Durable Galvanized Iron Structure] Each set of Sliding Door Wheels has a strong galvanized iron shell, which is passivated to prevent rust. The integrated casting design ensures the durability and service life of the thickened surface. 2 The following wheels can carry a load of 50 kg [Anti-track Design with Adjustable Screws]: The Sliding Door Caster is equipped with a double spring system to provide strong support and smooth and elastic movements. The anti-derailment device can ensure that the wheels are kept in orbit and the adjustable screws allow you to finely adjust the height of the door [Silent Scroll Performance]: Sliding Wardrobe Wheels are made of high-quality nylon, lightweight, durable and wear-resistant. The rolling wheels ensure quiet and stable operation and avoid noise during use. This feature makes it very suitable for bedrooms, living rooms, and other quiet environments. [Specific Track Compatibility]: The roller sign slider is specially designed for monorail -UPS with a size of 39.5mm to ensure perfect match and reliable performance. Compatible with some guide rails in the following round, as shown in Figure 2 to ensure the best function and stability. [Easy to Install, Widely Used] This package includes 4 pairs of sliding door rollers and 32 screws. No special tools are required. Our sliding door orbital wheel is an excellent choice for various applications, including sliding doors, windows, wardrobes, exposed cabinets, etc.