Plastic Ball Socket (A7) ISO9001:2000 Material: Plastic Plastic Ball Socket (A7) Material:Bll housing: Plastic, Steel clip: Spring steelThreads: M6, M8Width between centres: 18mmISO9001: 2000High quality, low priceMany types are available for chairs, automobiles, cupboards, etc.The articles also can be made specifically according to your own specifications.