This is a useful device that displays angles digitally. There are many of them and they are all about the same. My biggest gripe with this product and many of its competitors is that they are not flat on both sides. In fact, ideally they should be perfectly flat on both sides and possibly have a pendulum coming out of the middle. You want to be able to push it as straight and precise as possible from an edge or two against a very flat surface. For this, the design has to be optimized. Instead, they are designed more like novelties. There may be a slightly smaller version of this product and I would choose it instead of this one. Despite this shortcoming that I have outlined, I use this tool quite frequently to assist in DIY jobs.