The motiongrey rollerblade casters are designed to fit on any gaming chair series that we offer and are universal to 99% of office chairs produced in north america. These rollerblade wheels eliminate the need for chair mats and increase the mobility of your office chair. Installation is as easy as pulling the old casters out from the chair base and replacing them by pushing the new casters in place. features: fit: universal fitting stem fitting: 0.87in (2.2cm) (does not fit with ikea chairs) weight capacity: 650lb (295kg) wheel diameter: 2.95in (7.5cm) certification: bifma and ansi materials: steel bracket, polyurethane wheels, and precision balls color: matte black, steel silver use case: safe for all floors quantity: comes in a set of 5 package: boxed package included in box: 5 x motiongrey casters, 2 x gloves • safe for all floor surfaces: protect your floors with our motiongrey soft and strong high-grade polyurethane wheels which guarantee to not leave any marks or scratches up on any surface. • smooth rolling action and durable materials: our pulselabz caster wheels are made of top-grade steel and premium polyurethane. Precision ball bearings combined with vibration-reducing tires will give you a smooth and silent roll. Smooth transition on all types of floors including but not limited to hardwood floors, carpet, tile, concrete, stone, or vinyl. • universal standard & huge weight bearing：11mm stem size—7/16" wide x 7/8" tall (11mm x 22mm) fits up to 99% of office chairs sold across canada. Each caster can rotate up to 360 degrees and 5 casters can load up to 300 kg. • very easy to install: no tools required; just pull out your old office chair casters and push in your new wheels until the stem is firmly seated and secure; also includes a free install guide.