Pros : These work well with my Beetle Bits cutting system. I'm picking up some more of these to expand my working area when I uses these tools. Though they look gray in the picture, they are clear. The little squares catch debris.
Cons : Sometimes the male end seems to stick to the groove so tightly I am afraid one of the male ends which locks the grids together may crack. Also, if you are using a grinder near the waffle grid, sometimes the combination of glass dust and water gets on the grid and stuck in the squares. To clean, you have to run it under water.