Roll Fully adjustable rollers ensure smooth and safe sliding. This sliding door guide can be used with 3 inch thick doors, suitable for all brands of building doors . Easy to install, attach 2 screws to the bottom plate, adjust and tighten. Bearing Built-in bearing provides ultra-smooth bearing, easy to use. Frame Carbon steel frame with black surface, screw matching for maximum durability. Product Description Features: Fully adjustable rollers ensure smooth sliding and securely. It can be used with 3 inch thick doors, suitable for all brands of barn doors. Easy to install, attach 2 screws to the bottom plate, adjust and tighten. ultra-smooth bearing, easy to operate.Carbon steel frame with black surface, screw matching for maximum durability. Specifications: Condition: 100% Brand New Material: carbon steel Black color Optional type: single roller, double roller, double roller with a small roller Thickness Size: approx. 0.5cm / 0.2in Size: approx. 12 * 5 * 6cm / 4.72 * 1.97 * 2.36in PackageList: 1 * Guide floor 1 * screw bag accessory Note: 1. Please allow 1-3mm error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same and item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.