UNIVERSAL FIT: Standard 7/16" diameter stem perfectly fits most office chairs. Wheel replacement is effortless, no tools required. Simply pull firmly to release the old wheel assembly from your chair. Install the new AmeriGrip wheels by pushing into place. PRECISION BALL BEARINGS: Heavy-duty polyurethane wheels are designed for silent and smooth rolling motion. Upper and Lower swivel bearings allow for effortless rotation. SAFE FOR ALL FLOORING: Premium soft, polyurethane wheel material won't scratch, mar, or damage expensive floor surfaces, such as hardwood, tile, VCT, vinyl plank, marble and carpet. These all surface wheels eliminate the need for unsightly office chair mats. STRONG & DURABLE: These high performance, superior grade wheels feature solid steel riveted axles for the set to safely support up to 650 pounds. STYLISH DESIGN: Instantly upgrades any standard office chair to a modern, highly functional aesthetic & ergonomic design. The exceptionally clean, sleek look makes them the perfect addition to any office. Add functionality and stunning design to any standard office chair with AmeriGrip premium-quality replacement wheels. Crafted from heavy-duty polyurethane, our wheels are designed for silent and smooth rolling motion, eliminating the need for unsightly office chair mats providing an exceptionally clean, sleek look to any office. Upper and lower swivel bearings allow for effortless rotation. These high performance, superior grade wheels safely support up to 650 pounds for the set and are designed with a universal stem size made to fit 99% of all standard office chairs. Easy to install. Wheel size: 3" Diameter. Stem size: 7/16" (11mm) diameter x 7/8" (22mm) length.