Usage Tips:Dual Wheel Design - The universal dual wheel allows more surface contacting the ground, which can promote the smooth movement of the equipment without marks, and it is more convenient to replace the casters. This is a kind of elastic material resistant to wear and temperature.Which contribute to smooth mobility and low noise during movement,these casters can keep smooth and silent even under heavy load. Easy to install, whether the wheel is threaded rod or circlip type, as long as the rod length is 23mm to 26mm, and the piston diameter is 8mm, you can use this wheel without rod. Line up the holes and press them in. Scope of application - these casters are very suitable for furniture, office swivel chairs, computer chairs, small equipment, swivel chairs, swivel chair accessories, etc. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.