1. Material: nylon plastic + metal 2. Thickened plastic material, mute rolling, smooth and flexible, convenient and durable 3. Scientific and reasonable load-bearing pivot point design, safe and stable 4. Ergonomic design, smooth operation, easy to slide and rotate 5. Easy to install, soft surface contact, protect the floor from scratches 6. Weight: about 95g 7. Size: about 7.5 x 5cm