Features: 1. Made of high-quality ABS and materials, wear-resistant and durable, has a long-term possession, service life. 2. Easy to install: Adhesive design, installed on the bottom box, no complicated process. 3. Caster rotation and precision ball bearings in the shaft make rolling easier. The internal bearing of the wheelchair foot roll quickly, the surface is smooth, and it will not be jammed by crumbs, hair, and sand, and you will enjoy smooth and quiet movement. 4. No noise and scratches: With unlimited durability and high shock absorption. These casters allow you to roll smoothly and quietly without making harsh noises, and ensure that you don't scratch or leave marks on any surface. 5. Scope of use: The wheels are suitable for different types of storage box, making it easier to move. Specification: Material: ABS+glue Size: 2 x 3cm Notice: 1.Due to the different monitor and light effect, the actual color may be a slightly different from the picture color. 2.Please allow 1-3cm differs due to manual measurement. includes: 4pcs x Storage Box Pulley