The sg 72 cutting guide is a specially shaped guide designed specifically to accept aero shaped seatmasts and seatposts up to 35 inches 89 mm deep the guide can also accept round tubes from 1 14 inch to 1 34 inch 32 mm to 45 mm in diameter two cutting slots are provided one for standard saw blades and one for thicker carbon specific blades hardened steel body with moulded contact points to priotect tubes and frames