Set of 5 Rollerblade Style Office Chair Caster Wheels for Hard Floors 3" Diameter, 7/16" Diameter x 7/8" Length Grip Ring Stem, Made in USA will NOT Yellow Wheel will not yellow over time. Proprietary type of plastic is used. UNIQUE SCRATCH FREE DESIGN - Never worry about your wheels scratching your floor again. PVC Design allows for smooth roll without damage to floor. Heat treated raceways for increased wear resistance 120 lbs capacity per wheel combined capacity of 600 lbs max. 3" DIAMETER allows you to transition from any floor to another. Tile to Carpet, Hardwood to Tile, Carpet to Cement, Vinyl to Rug. The size allows transitions to be easy while in or out of the chair. Sturdy bearings that will last. UNIVERSAL SIZE allows these casters to be used on almost any chair. Don't settle for the cheap set that comes on your expensive chair upgrade to high quality wheels that will last forever! Made in the USA.