Soft aluminium, 33-gauge design. Concave step straddles router bit or saw blade for precise height adjustment. Step on top edge acts as gauge to test depth of completed cuts. Step on end sets distance from tablesaw blade to fence, or router bit to fence. Includes 3/175mm (1/8″), 4.762mm (3/16″), 6.35mm (1/4″), 8mm (5/16″), 9.525mm (3/8″), 11.112mm (7/16″), 12.7mm (1/2″) bars.