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) Easy Installation: The caster wheels heavy duty are also very convenient to install. If there are existing mounting holes, just pull out the old one and insert the new one. If there are no mounting holes, you need to drill holes (23/64 IN), tap the sockets into the drilled mounting holes, and finally tap the caster into the sockets. Installation is complete, which takes about 5 minutes Protect the ground: The stem casters is made of PP material, a thermoplastic synthetic resin with excellent performance, heavy duty caster wheels which has excellent bearing capacity while maintaining a smooth . This effectively protects the floor from marks and damage from quiet sliding Excellent service: You have these products in the package you receive, they help you work better Color: As shown Material: Pp Package Contents: 4X ball furniture casters 4X stem sleeves Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.