Standard Chairmat Casters, 7/16" x 1-3/8" Stem, 75 lbs./Caster, Zinc, 4/Set (30701) Economical 2" single wheel caster for use on all types of home or office furniture and equipment. Soft rubber wheels for use on chair mats and hard floor surfaces. 7/16" dia. x 1-3/8" long stem fastener for metal bases. Weight Rating: 75 lbs/Caster. Zinc Finish. 4/Set. Made in the USA.