This #22 back has a 1-1/2" long threaded nail. When anchored with a spring lock washer, the threaded nail is a fast, positive alternative to prong tufting. Just insert the nail through the upholstered construction and fasten it on the back with a spring washer. Use our Spring Metal Washer (ITEM # BMPWWAS105- NOT INCLUDED) This item is sold in a 1 gross box (144 pcs. of each item).