Optiparts Plastic Pennant Plugs. Sold as a pair.
Used exclusively on racing masts (two holes at the top of the mast in place of two eye straps). Tie your two top sail ties to these and insert through the two holes at the top of your mast.
Insert the staff of your wind indicator into the top inside of you mast and through the slots of both pennant plugs. Locks your sail ties and wind indicator all in one easy step. Allows for quick rigging and the ability to slide your sail off of the mast without untying your sail ties.