The Ultimate in Accuracy You've never seen anything better for marking a perfect 90 degree angle. Use for marking metal, wood, plastic, etc. Hard-to-find small sizes are a must for dollhouse miniaturists and modelers. Also excellent for setting up small table saws, disk/belt sanders and other tools. Made of fine quality, fully ground carbon steel. Set includes: one 3 inch blade, 1-7/8 inch beam; one 4 inch blade, 2-1/2 inch beam; and one 5 inch blade, 3 inch beam.