We recently ordered your heavy duty dog door to be installed in our garage door. We have a 14 year old Border Collie, a 5 year old 110 pound lab and two 4 month old lab pups. I am happy to say that all four dogs have adjusted to it very well and use it regularily. This gives me peace of mind that they can roam the farm and play and get shelter from the cold weather that we get in Alberta Canada. And needless to say the peace of mind knowing that the lab pups won’t be able to destroy it. Thank you for designing such a great door.