Product Description 1. The “O” ring or “X” ring will greatly reduce the wearing and the service life by 3-5 times.2. Model: 420V, 428V, 428VM, 520V, 525V, 530V, 530VM, 630V, 630VM, 428V-X, 428VM-X, 520V-X, 525V-X, 530V-X, 530VM-X, 630V-X, 630VM-X, 420Hz, 428Hz, 520NZ, 525Hz, 530Hz, 630HT3. Color: Self, gold, nickel, blue, red, orange, green, yellow, pink…