chair caster, chair swivel chair caster wheel nylon,dia 50mm, with 11*22 metal pin,chair caster, BIFMA standard or NON BIFMA chair caster, swivel chair caster,caster wheel1)chair caster, nylon ,dia 50mm,2)chair caster, nylon ,dia 50mm, , BIFMA standard.3)With brake or without Modern style & exquisite quality. chair caster