Service Caster listing for set of 5 (five) Ultima twin wheel casters with 2" (50mm) nylon wheels and grip ring stems. Nylon replacement twin wheel caster for chairs, tables, plant stands, ottomans, furniture and light equipment. 75 pound capacity per caster. Mounting height is 2-1/4". Grip ring stem size: 7/16" diameter; 7/8" length.