For measuring and marking outside, inside and sloped angles. 
 Base is grooved at 30, 45 and 60 degree angles on both sides for precise setting of ruler. 
 Rule can be used as a depth gage for measuring small holes and slots. 
 Protractor-style markings on both sides of base. 
 6" x 1/4" etched stainless steel rule is graduated in 32nds and 64ths. 
 Spring-tension nut holds rule securely in position. 
 2-1/2" hardened steel base. 
 Conforms to government specifications GGG-G-17b.