I wanted a decent t-square, that wouldn't break the bank. Unfortunately, there are many choices online, and it is easy to make a product look cool, which is why cheaply made goods are becoming the norm, while quality made goods must be found. I feel like I hit the jackpot. This ruler is well made, light weight but not flimsy, the head seems to be made of a high grade ABS and is solidly mated to the ruler. The numbers seem to be silk screened on. Considering that this will only ever be used gently, though frequently, I feel confident that the numbers or markings will not wear off anytime soon. I don't have a proper drafting table, but using the edges of my desk, this makes a very nice 90 degree angle even using the last 4 inches of the blade. I did notice that there appeared to be a hairline rise in the plastic under the blade on mine. It caused an extremely small wobble when trying to set the square flush to the edge of the table. It might have been .001 of an inch high. I laid a razor almost parallel to the surface, and ran it back and forth until the bump was almost imperceptible (and it would be to anyone who did not know it was there), and the wobble is gone. It sits cleanly and flush against the edge of my desk. If you use the inside measurements closer to the T blade, you can draw as accurate a line as you need by using each side to set your end points of the line, and then drawing it out between the points. To test its accuracy, I drew parallel lines, one from the top of my table, and one from the bottom of my table. This lets me use the full length of the blade and verify it sits perfectly at 90 degrees. Mine appears to be off by an extremely thin margin but not so much that it would affect the work I do. This has 5 set screws, so you could theoretically calibrate your own square if you needed perfection. All said and done, I found some minor flaws that are easily correctable and might not exist on others from this brand. Also, since I do not have a drafting table, it's entirely possible my desk edges are not perfectly parallel, and may account for any perceived inaccuracies in its angle, which is stated calibrated at the factory, so take my review with a grain of salt. Frankly, this is well priced for this size and quality, and any issues I perceived are correctable.
