<https://micromark.com/ko/products/steel-machinists-squares-set-of-3#product>
<http://schema.org/description>
"The Ultimate in Accuracy    \n    \n\nMade of fine quality, fully ground carbon steel\nMarks a perfect 90 degree angle and is a quick check for 90 degrees\nUsed for marking metal, wood, and plastic\nUse to set up table saws, disk belt sanders and other power tools\nSet of 3; 3 inch, 4 inch and 5 inch blades    \n    \nThe design includes a base and blade set at precise 90 degree angle. There may be a small notch at the base to prevent accumulations of debris that could throw off the measurements.    \nIncludes three squares in the following sizes: 3 inch blade with 1-7/8 inch beam; 4 inch blade with 2-1/2 inch beam; and 5 inch blade with 3 inch beam."
<https://micromark.com/ko/collections/measuring-marking/products/steel-machinists-squares-set-of-3>