1mm thick steel plate from the machine stamping, it has the capability to support a 15KG payload. The Caster is strong and lightweight. It has 20mm high round body, with a total weight of only 37g. A large steel ball around a small ball around as much as 40 to rotate the main scroll ball much more smoothly, which makes the robot walk or move in a more flexible and comfortable way. Our popular 2WD Arduino Platform adapts this caster.