ZVH1126 Features: * Professional carpenter""s combination square * Ultra test combination sets * Specially designed for carpenters and the woodworking trades * Machined and enameled cast iron head has precision level and scriber for producing right and 45 angles * 12"" x 1"" Steel blade is graduated in 8ths, 16ths, and 32nds * Conforms to government specifications GGG-S-656C Assembly Instructions: * Clamp assembly * Clamp assembly is spring loaded to hold the protractor heads and body to the steel ruler