Safe for all floors - no chair mat needed - These office chair caster wheels are encased with a high-quality, extra-thick non-marking soft polyurethane layer to stop scratch or leave marks on any surface even if there is no carpet or chair mat. Widely used for the office floors, wood, hardwood, parquet, laminate, vinyl, tile, and carpet floors | Smooth and quiet rolling - No squeaking and rattling from your office chair anymore. Precision ball bearings and a soft polyurethane wheel-shell make chair rolling silky smooth and quiet on any surface without disturbing anyone. The rubber chair casters designed for universal standard stem size: 7/16 " x 7/8 "(11x22 mm), suitable for 99% office chairs brands of Miller Steelcase, Aeron, Herman, Dxracer, Humanscale Freedom, Lazyboy Serta, Hon, Boss, etc. IMPORTANT: Not for IKEA chairs | Heavy-duty construction - To avoid slips and increase friction, our chair caster wheels adopt roller skates technology and passed the top-level test of BIFMA and ROHS. The chair casters built with sturdy steel structure with premium dual-steel ball bearings and PU rim could strong enough to load up 650 lbs by a set of desk chair wheels | Easy assembly - Your office chairs will look more attractive by using these office chair caster wheels. Our caster wheels did not require tools for replacement, simply pull out the old wheels from the chair base, push the stem of your new chair wheels into the socket and finish in 10 minutes | Quality management - All our products are produced under strict quality inspection. If you have any problems with our product. Contact our Professional after-service team, our direct after-sale team will reach out to you and timely solve your problems