Grand Master has a 60-degree carbide insert with a 5/16" steel shank. A 1.200-inch head makes for a larger anchor to distribute pressure over a wider area on single-ply track. Big Nut ALN2-4500 is included with the 1.325", 1.450". The 1.575" length bolts are packaged with ALN2-7000 Large Nut. This bolt can be used on a traditional 2-ply track. The 2.52 one track Single layer cannot accommodate Round Grand Digger backer plate Use Grand Digger Square and Double.