When it absolutely, positively needs to be quiet?Master Caster Noiseless Casters are the solution. Dual ring patented technology eliminates excessive noise. Specially designed stem provides quiet mobility on all floor surfaces. Eliminates black powder residue created by metal-to-metal friction. Perfect for hospitals, libraries, schools and offices?anywhere quiet is necessary. 2 3/8" diameter Euro-style designed to make the chair leg and caster appear as one. Caster/Glide/Wheel: 2 3/8" Futura Casters; Color: Matte Black; Stem Type: B; Weight Capacity (text): 100 lbs. Per Caster.