●Urethane chair casters made of rubber and urethane are lightweight yet sturdy, and smooth to move and wont scratch your floor ●Easy to install with drop-in casters Compatible with chairs with 0.4 inch (11 mm) diameter insertion holes ●Insertion rod diameter: 0.4 inches (11 mm), Insertion rod length: 0.9 inches (22 mm), Caster diameter: 2.0 inches ( ●Compatible with OA office chair, computer chair, mesh back chair, baron chair, etc ●Large casters with a diameter of 2.0 inches (50 mm), each caster has a load of about 55.1 lbs (25 kg), and the set of 5 can hold up to a maximum weight of about 255 kg