U.S. UTILITY PATENT: caster system for moving furniture. STEALTHO INNOVATIVE WHEELS - 920% CROWDFUNDED ON KICKSTARTER: Brand new office chair caster wheels from STEALTHO with the totally reconsidered design. NO CHAIR MATS NEEDED - SAFE FOR ALL FLOORS: Our pemium office chair swivel wheels are safe for any kind of the hardwood floor, parquet, laminate, linoleum, tile, carpet. Simple office chairs wheels replacements for you! SMOOTH & QUIET BARRIER-FREE ROLLING: High-tech elastic polyurethane of our office chair wheels makes movements easy and noiseless. These chair casters for hard wood floors will glide smoothly. NEW STEM DESIGN & HEAVY DUTY ABEC9 BEARINGS: New geometry of our heavy duty casters prevents axial run-out bearing of our chair roller wheels CARE CUSTOMER SERVICE: If you have any questions, please don't hesitate to contact our Customer Support by clicking on our seller name " STEALTHO" that you should find on the right side under the "Buy Now" button because we are 100% committed to your happiness as a customer