1. Remove the old tire from both wheels and clean any remaining adhesive from the steering wheel. 2. Note: Do not use glue or other hard plastic adhesives. You can use general-purpose adhesive, 100 plastic adhesive, or neoprene adhesive. 3. After completing the plastic application, wait 5-8 minutes before attaching the wheel. Allow 24-48 hours before use. Positive and Negative Distinction: The treadmill mop is divided into two parts: one part is placed on the ground (called positive) and the other on the wheels (called negative). When replacing the tire skin, it is important to distinguish between positive and negative placement. **Positive**: From the outside, the lines are vertical. **Negative**: From the outside, the lines are horizontal. Positive has less resistance, while negative has greater resistance. If placed incorrectly, durability may be reduced and the lifespan may be shorter. Material: Plastic Color: Black Package Contents: 4 * Caster Wheels Only the above items are included in the package; other products are not included. Note: Lighting and different displays may cause slight color differences between the item in the picture and the actual product. The measurement allows an error of +/- 1-3cm.