This, my friends, is a point turner. It looks like this particular one is set as a button gauge as well. However, my main focus is on what the point turner does. It is so helpful when you are sewing a project that needs to be turned inside out and of course has corners.
This will make your life much easier! For instance, I used it on the pockets of my purse that I just made and put on here.
Anyway, it's pretty simple to use: push the pointy side into the corners and watch them come inside out with ease!