I use them all the time in my woodworking hobby. From holding items while gluing to working as heavy sanding blocks and holding items under a small power drill. They come in pairs, and to my inexperienced eye the pairs appear identical. I haven't measured them with calipers or anything as I don't use them for precision purposes, but it's nice to have blocks that I know are square or close enough. If you do serious editing work. It can be worth investing in higher quality blocks, but they're pretty good for my purposes. They are a good weight, easy to stack and come in pairs.