The positioning ring is an accessory to down-thrust clamps 23310.0050 - .0058, 23310.0083-0088 and 23310.0070.
After aligning, the clamp positioning ring is fitted on the spindle with the effect, that repeated clamping is always exactly on the same point. The positioning ring is rotating by 360° on down-thrust clamp. After mounting, the clamping claw can swing 110° to the left or right (only for the swiveling versions).
Before mounting the positioning ring, pull-off the clamping claw of down-thrust clamp.