Upgraded Version: Adjustable floor and wall guide. Provides stability and smoothness to your sliding door. The smooth roller won't damage your door. Beautiful and practical. And thanks to the easy installation, it's perfect for both experienced and inexperienced users. Material: The sliding door wheels are made of robust steel and nylon outer parts to provide superior product quality. The outer layers provide a smooth surface that can reduce the friction caused by iron sliding doors; In addition, they provide durability and impact resistance. Humanization: 1. Hot-dip galvanizing, 2. Zinc layer thickness: 120g3. Salt spray test life: ≥72 hours (no rust) 4. Error: ≤50mm. Application: Electric door on wheels/wheel with nylon sleeve for sliding door/iron door with wheels/electric door guide wheel/wheel/pulley. Easy to Install: The sliding door kit can keep the door perfectly balanced on the roller guide and prevent wobbling. The wheel rollers can also be used as a sliding door guide so that the sliding door hardware does not produce noise and is balanced. Perfect for sliding garage doors, interior doors and gates, etc.