Aircraft aluminum - 5 stars - Stainless steel ruler - 5 stars - Huge plus for setting a bubble level 6 stars Sharp edges at 45 and 90 degree angles, BUT BUT burrs on both corners that need attention [wet sand to make it smooth]. You're getting $13, better than most in the price range, hoping you don't expect the nice (orange) finish to last long without chipping (minimum). So I didn't check the photos. Good for $13 [with my simple sanding/polishing on smooth surfaces] Better than a zinc die head. out of the box [actually a very short cardboard half-sleeve. Enough to hang on a hook in a retail store. It's just a good combo square with its limitations and smaller than the description Ion would have us believe. It's $13 and that's what you get. Despite [NASA's] reference to "aircraft quality." The bubble level setting is the best "style" I've ever seen. if you use/trust the plane in this way or for this purpose. The writer was lying loose in the shipping envelope, but survived the journey. Perhaps it should have had a small silicone o-ring [which I will add] to keep it intact with the tool. at least you get it. It costs $13. with effort. but it COULD be a GOOD $13 square with a little more care and love. Again, this review costs more than the tool, but YOU are worth my effort to convey the truth. God bless you.