Used to keep the corners of the outer cat cage square. Would use to secure the 2'x4' corners and then use a nail gun to assemble the corner. Worked very well. They held 2" x 4" nice and safe. Doesn't slip or come loose. I could only do one lap at a time, but that was ok. I'm just a DYI guy so I don't need 4 of these. (Well I'd take them if you give me one.) We used plastic squares with clips on the other corners. They worked much better and easier. I'll probably use a little more for my next project.