HHIP Dasqua 4 piece combination square set with 12" blade includes a square hear, a center head, a protractor and a blade. The blade is made of hardened stainless steel. The double indexed protractor is graduated 180 degrees in both directions. The blade is marked with graduations 0. 5mm and 32nds and 1. 0mm and 64ths. Accuracy is +/-15. Supplied in a sturdy, fitted plastic case.