1. 2-inch diameter twin wheel with soft roll rubber wheel surface, no marking on carpets or any kind of natural and engineered wood floor, tile floor, 2.Laminate, Tile, Slate, and all other Hard Floors

3. Stem Length: 7/8". Stem Diameter: 7/16" -- universally fit all office chair bases with 7/16" (industry standard) mounting holes

4. 90-lb load capacity per caster, total 450lbs

5. Twin wheels allow for more surface area in contact with the floor and move in opposite directions to minimize carpet fiber twisting

6.Easy pull and snap installation

7. Fits most office chairs