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. 2in diameter dual black wheels for use on all types of furniture. Caster/Glide/Wheel: 2in Duet Casters; Color: Matte Black; Stem Type: R; Weight Capacity (text): 100 lbs. Per Caster.