Deluxe Duet Noiseless Casters are perfect for when it is absolutely, positively needs to be quiet. Dual-grip ring technology eliminates excessive noise, providing quiet mobility. Duet twin-wheel casters complement all types of office and home-office furniture. The 2-3/16″ diameter, dual, hooded wheels with specially designed 1-1/2″ diameter neck fit 1-1/2″ diameter chair bases where chair base and caster fit together to form a solid unit. Hard wheel casters are designed for safe rolling on carpeted surfaces, preventing stress and strain to leg and back muscles. Stem fastener measures 7/16″ diameter x 7/8″ long. Each wheel is rated at 120 lb.