The Swanson Savage 12" Combination Square is great for laying out lines for ripping, crosscutting, mitering, & making notches. The head, with fences at 90 & 45 degrees, slides along the blade & locks, allowing you to transfer a distance accurately & hold it while you draw a line with a pencil. The Combination Square is right up there with the claw hammer, pencil, & tape as tools that every carpenter carries all the time. Small enough to fit in your back pocket this tool is indispensable.