I did my homework between Starrett and iGaging and decided it was worth it as many reviews said iGaging was comparable in price. I received my first iGaging square combo kit and did a "line test" to check squareness, but it failed miserably. Suspected doubts and demanded an exchange. The 2nd combo square also failed, albeit by a smaller margin, but still unacceptably. I'll pay the same money and get a Starrett head, and in time I'll buy other heads. A square of a damn egg isn't worth it if it's not square.