Master Caster 64234 Safety Casters, Standard Neck, Nylon, 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. 5/8" standard size dia. neck. Hard nylon wheels for use on carpeted surfaces. 7/16" dia. x 7/8" long stem fastener for metal bases. Weight Rating: 110 lbs/Caster. Matte Black Finish, 5/Set