We use high quality pp composite co-polymer material to make the trolley. It is durable and will not break down easily. And the caster wheel is PVC or rubber. It has great wear-resistance and it is silent when we use it. It will not damage the ground. About the wheel , it is Double ball bearing which requires less effort. Load capacity is 200 kg and 400 kg. You could choose the right size based on your need. Any inquiries, pls contact email@example.com. Wechat / Whatsapp is +86-18033305520.