aluminum screen rail and spline with the plastic corners from home depot for the top, bottom and sides. The doors I used a pnuematic staple gun and hot glue on wood frames. The screen for the doors is petscreen (PVC coated nylon). Its much easier to work with and does not damage nails when climbed on. I use that on my adult cages. The only drawback is that you cannot see through it as well as aluminum screen.