The Delta 31-817 is a pack of 4, 80 Grit Pre-Cut Sanding Strips for 31-250/252/255X Drum Sanders. The Delta sanding strips are pre-cut to fit the 5” x 18” drum of the 31-250 wide drum sanders. The Delta strips are coated with aluminum oxide abrasives for long life and a smooth finish. The pre-cut sanding strips also have a cloth-backing for maximum strength.