[Mute and prevent scratches] The height of the fixed feet of office chair glides is close to the height of the mounting feet. It is suitable for preventing the air pressure rod from damaging the floor. [Suitable for all kinds of floors]Fixed stationary castors have good traction, maintain stability on smooth floor surfaces (wood, tiles, laminates), provide greater traction than casters, and reduce friction, vibration and noise. [Excellent caster replacement]Replacement glides are suitable for different swivel chairs (executive chairs, office chairs, game chairs, tables and chairs)very suitable to roll the stool or office chair into a more stable fixed type. [Efficient installation]Replacement office chair wheels are easy to install and remove, no screws are required, just grab the old casters and pull them out. Then push chair wheels replacement into the holes. Good traction for smooth movements: These sliding devices maintain stability on smooth floor surfaces (such as wood, tiles, and laminates) while providing greater traction than casters. Easy to install: is very easy to install without any tools. than casters: By avoiding the "rolling chair effect" when up from a table or desk, a seat is provided for people who have difficulty in and out of the chair. Protect your carpet: will not chew carpet like some well-known casters. -perfect for atypical situations: perfect for moving surfaces, such as boats and RVs, and floors that are not too flat. Heavy-Duty & Super Quiet Fixed casters have good traction, maintain stability on a smooth floor surface, and provide greater traction than casters. In addition, we also give 5 foot pads to help you reduce friction, vibration and noise. Colour: black Material: nylon Size: Base diameter 52mm, plunger: 11x22mm, installationheight 35mm Package Contents: 5 * Swivel chair fixed casters 5 * Foam pads Only the above package content, other products are not included. Note: Light 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.