1. Made of high-quality materials, durable and practical. 2. The wheels are severely worn and cannot contact the rough ground, and the sliding resistance will increase. 3. The wheels cannot contact the ground, causing the shell to scratch the ground for a long time. 4. Long-term friction of the shell will cause a series of chain reactions such as burrs, wear of the bottom cover, and brush falling off. 5. It is recommended to replace the wheels every 6-12 months. 6. Material: plastic + stainless steel
