Master Caster 64335 Safety Casters, Oversize Neck Polyurethane, B Stem, 110 lbs./Caster (Set of 5) Patented Roll Control Internal brake prevents wheels from rolling freely when user stands. Allows smooth effortless chair rolling while seated. 2" diameter dual hooded wheels. Oversized 1-1/2" dia. neck fits 1-1/2" dia. chair legs creating the illusion of a solid unit. Soft polyurethane wheels for use on chair mats and hard floor surfaces. 7/16" dia. x 7/8" long stem fastener for metal bases. Weight Rating: 110 lbs/Caster. Matte Black Finish, 5/Set