High carrying capacity: The material of the sphere is made of PP material, which has good heat resistance, insulation and resistance. The wheel cover is made of heavy-duty steel structure, (including 4 installation sockets), which greatly improves the bearing capacity of the wheels for furniture, up to (500 LBS), the overall hardness is uniform, and the friction is good, which greatly prolongs the use of the chair casters Wide Application: The industrial casters is suitable for a variety of applications, whether it is indoors or outdoors, it works well. Including but not limited to: cabinets, coffee tables, plant stands, shoe boxes, sewing chairs and other equipment. Please confirm size before purchase (caster 5/16 IN x 1 1/2 IN (8 x 38 MM), suitable for 3/8 IN hole, (direct insertion mounting hole) but not suitable for 3/8 IN socket. Included Socket of 9.1x31 MM/0.36x1.2 IN(D * H), Weight: 1.53000809828 Pounds, Manufacturer: NONDK