I purchased one of your heavy duty gun dog dog doors about 3 months ago for my new yellow lab puppy. I wanted to write to tell you how pleased I am with your product! Installation was very easy and the instructions were clear and easily understood. The door works exactly as advertised and the puppy quickly caught on to it’s use. I am anxious to see how it stands up to a Michigan winter, but given what I have seen so far I am confident in my continued happiness. Thanks for a great dog door!