Semroc Bulkhead or Block ST-7(2 ring Set) SEM-CR-7P
Used as lightweight bulkheads for gluing on the end of a ST-7 coupler, one ring fits inside the coupler and one on top to match the ID of the tube.
Center hole for a Screw eye
Thickness assembled: 0.25"
Diameter: 0.715" and 0.759"