The Z-Ring deforms when assembled, creating a spring effect that
produces a long lasting seal. The special Z-Ring section enhances
chain flexibility and smooth operation. The conical section of the
Z-Ring provides accurate positioning on the bushing. The lubricant
is trapped between the plates and the lobes of the Z-Ring, keeping the
Z-Ring lubricated and prolonging its life. Size: 5/8 x 1/4 (520).