Dimension of insert stem: the standard 7/16 x 7/8 inch (11 x 22 mm) grip ring mounting stem to attach to most standard chair or stool bases; Suitable size can meet your needs; Please measure your size before purchasing. Overall glide height: 2 inches overall glide height when installed, fits for most small chair casters; This stool office chair bell glides can convert office chair with casters into a stationary chair without losing the chair height; Please check whether the product is suitable for your chair before purchase. Bell glides size: these bell glides are 2 inch in bottom width and 2 inch overall glide height, similar to most small chair casters. Practical design: with solid PU structural glides design, can handle more weight on most of desk chairs, workshop chairs or any other stools, etc., black color also can easy to match different chairs. Protect your floor: glides replacement has soft bottom can protect your soft floor better, and the package includes felt pads also can provide an extra protection on floor surfaces. Easy to match different chairs, material, thickening and durable, can be an economic chair wheels replacement. Match with felt pads not only can protect your floor better, but also provide people with a more safe seat, avoid injury by a rolling chair. Material:PU, metal colour:Black Package Contents: 5 X Fixed Stationary Castors(52mm) 5 X Felt Pads(40mm) Only the above package content, other 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.