At 6" × 12", the large precision square has the accuracy of an engineer’s square (0.001" per inch of length), with all four edges ground and both faces graduated on the inside and outside edges
For ease of reading, the markings are etched and black-filled
The chrome-plated high-carbon steel legs can be marked upon with pencil for direct-reference use
The interior corners are relieved to ensure that the square seats well, even over saw whiskers
Beyond being useful for layout work, the square lets you check if surfaces are flat or straight, and can measure and check for square on the same plane
It has 1" wide legs graduated in 32nds on the 6" leg and in 16ths on the 12" leg