I was hesitant based upon other reviews but some of those were older and I was hoping things were better. They were. There was only one screw slightly beat up. Everything was clean, fit well, and lightly oiled for shipping. The surfaces with writing were satin finish, clear and easy to read. The measuring surfaces were ground and had typical ground finish on them. I compared to two different machinist angle blocks I had and they were, for what I could tell, all within 15 minutes of angle. Close enough for what I was working on. These are great for a shop use and machinist use. Are they tool room precision? I do not have the ability to determine.
Great value for the shop machinist and hobbyist.

For what I need (measuring the angles of existing weirdly-shaped products without clean, sharp corners) this is sufficient, but it probably isn't suitable for high-precision work. No instructions, calibration certificate is in Chinese, the slides don't feel very smooth, and the protractor itself says it's 8' off of perfectly level when closed to 0 degrees, but none of these are big issues. I'm going to guess that anyone buying as technical and specific of a product as this for $30 on Amazon probably already understands the benefits and can guess the likely limitations of buying a generic unbranded measurement instrument from China on the cheap.

It's a good thing I like toys. The reason I say that is, I have a significant layout tool collection grown out of both that I find myself laying out everything from straight lines or circles and arcs, curves to letters and numbers, so I find need for verifying a variety of setups and layouts.

For the foregoing reasons, I have all manner of triangles, rulers, straight edges, tapes, compasses, curves, gauges lettering templates and so on. Some are more useful for a given project than others.

Since I took up turning last year, I find myself experimenting with the bevel angles of my turning knives. If nothing else, I've learned:

1) experts are not experts on which angles best work for me [and my style of turning]; and,

2) just changing the angle of a grind five degrees, or even less, can produce vastly different results.

For the foregoing reasons, capturing an angle I found worked well for me is critical. To that end, I've looked to or bought different gauges to determine before and after angles of turning knives. For example, I've tried using a very common adjustable protractor to check angles, but the leg is too long. As such, I'd need to buy a second one and cut the leg down enough to allow me to use it on short turning knives. Until I do that, I won't know if one with a shorter leg worked for establishing angles on tools and things requiring the short leg.

Because they are inexpensive, I purchased one of the inexpensive, imitation brass, flat metal gauges you see available on line. To use one, you just stick the point of your chisel or turning knife into one of the several angles cut into the metal gauge and look for light. These have two drawbacks "“ they lacks the forty degree angle I need for some of my preferred choice of angles, and they seem to offer a different opinion of what some angles actually are, or are said to be, according to at least two other tools I tested it against.

I decided to test drive one of these gauges. This one appeared to have far more adjustability than any of my others. For example, the body can be slid right or left to over come the long leg problem of the first gauge I described. This appears significantly more accurate than the [fake] brass gauge previously described.

I went out in the shop and test drove this for setting the bevels on a couple gouges and a skews and believe I may have found what I needed to verify angles. You can slide the body up and down to allow measuring thick items, like ax heads, or down tight to the base to test the angle of a chisel. You can slide the body left or right to adjust the length of the leg, so it can be used on, for example, knives and chisels of all sizes. Finally, setting the angle is easy. A small adjustment knob on the back side lets the operator move the setting of the gauge in degrees or minutes in smooth movements.

The only reason I did not give this five stars is, it is not a three hundred dollar set up tool. It's a twenty-six dollar ($26.00), "what you pay for is what you get" tool.

Too, I do not, yet, know it's accuracy. When I find some of the machinist's angle gauges that came in a yard sale box of goodies, I may have a better idea and will post accordingly.

Actually considering how little I paid I got more than I paid for, but that still wasn't a whole lot.
If one compares it to a name brand protractor costing ten times as much, well then it looks like total junk, but for what it is it's kind of ok. One just has to keep in mind what it is and use it accordingly.

Typical Chinese metal product: usable but not well finished. Stainless steel except for spring, screws, rack and pinion. I broke it down, worked all the surfaces with diamond plates and it moves much better. Did I improve the accuracy? Probably not. So you don't need to fuss with it to have a workable tool.