This product is great. Im knocking down the core because of sizing. My exterior walls are made with 2x6 studs. One tunnel is not enough and a second tunnel piece was 3/4 too much. The sizing of the frames and the tunnel pieces could be made to have one tunnel fit both or 2 tunnels fit th 2x6 width. I made it work by using a 3/4 inch thick piece of plywood cut and stained to trime the inside and provide the extra with required.

I love my High Tech Pet door. It works perfectly and just as advertised!