... hook mouth Hardware 2 O Ring Mechanism(PR133-2-25/20) Material: metal1. Surface treatment: nickel electroplating, nickel free (through the ... , 264mm, 280mm, 285mm, 292mm, 384mm4. Inside diameter: 15mm, 16mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 65mm,78mm5. Shape of ring ...