Furniture Casters and Wheels Twin Wheel Desk Chair Caster 7/8" Grip Ring Stem First, there is a chip on one caster, see pic 2. It doesn't affect the wheel in any way. Add mobility to your furniture with our set of four (2 with brake) twin wheel casters. These casters are made of rigid plastic and have a modern style that will complement any room. They have a push-in mounting type and a 7/8" grip ring stem. The casters are compatible with universal brands and have a matte finish in black color. Each caster wheel is 3-1/4 inches in length, 1-3/4 inches in width, and 3-1/4 inches in height, including stem. They have a unit quantity of 4 and are ideal for any room in the house. They feature twin wheels for smooth and easy movement. Please see specs for more detail. Thanks for stopping. Please visit my slow growing store, read about me, my policies and view other items that may interest you. Also, I would be honored to be added to your saved seller list. **I always have money saving volume discounts on most items** David - thediscountretailer LLC