Here is the new rat cage I made for my boys with the new style Cube Grids I found at Target the other day.

This replaces their closet shelving cage, which I never liked my door solution on, and that they had chewed the coating off of, slowly but surely.

Comments on these new style grids:
1) The new coating is rubbery, and slippery, vs. powder coated. This made the connectors not 'grip' as tightly as they do with the original style of grid, and cable/zip ties are mandatory for holding the cage together, rather than optional. I hope the company solves this, as it will cause problems with these grids a shelving unit as well.
2) I am worried that the rats will take a liking to this rubbery coating, like they did the coating on the closet shelving. I am hoping that the squares are small enough that they cannot actually chew the mesh, but only time will tell.