I used these to make guards to keep our regular window screens intact. I previous has black grid panels and replaced with these white ones since we painted a different color. The black were used commercial and likely the industry standard. These are anything but precise. They are not square, the wire mess is very uneven and if you had to use hooks etc. that depend on exact spacing of the grid, it will likely be a struggle. I expected lesser quality due to the price and I wasn't disappointed. They did however, work for my use after some manipulation to square them up a bit better.