Flexi-Overdenture Stainless Steel #1 Red Refill: 6 Overdenture Posts, 6 Attachment Caps, 6 Rubber Bands, 1 Primary Reamer and 1 Countersink Drill. Flexi-Overdenture has a unique split shank of the Flexi-Post, with a ball and socket attachment for the highest retention and ideal distribution of stress. 6 post refill