Johnson Stair Gauge, Heavy Duty, Square, Brass, Johnson, 5-1/4 in Overall Height, 2-1/2 in Overall Width, 3/4 in Overall Depth, SAE, Used With Rafter and Carpenter Squares to Speed up any Measuring Jobs

Easy attachment to any rafter square. Use for angle cuts on rafters, or stair stringers. Can also be used as security stops on window or door metal channels.