Swanson 2 Piece Carpenters Speed Square Imperial. The Swanson Speed Square, is essential for every carpenter, construction professional, roofer and DIYer. Use this Speed Square to determine out-of-square corners, angles, etc. When used as a saw guide, the Speed Square makes truing up a board easy. Useful for determining and marking angles and making square cuts on boards. Specifications>/b>Big 12 Square Dimensions (Inches): 12 x 12Speed Square Dimensions (Inches): 7.25 x 7 x .875 Features and BenefitsMulti-tool: Try square, mitre square, saw guide, line scriber and protractor1/4" spaced scribing notches and the Diamond cutout for easy rafter seat cutsGraduations included for marking common hip, valley, and jack raftersHigh-visibility, black graduations with a non-glare matte finish ContentsSwanson Big 12 SquareSwanson Speed Square