Features: High quality aluminum construction. Clear flap allows pet to see if slide is in place. Tamper Proof Mounting System, pet door can't be removed from outside. Spring loaded Lockout Slide.
Door Sizes And Pet Weight: If your cat is smaller than about 15 Lbs or your dog is smaller than about 8 Lbs, a flap size of around 5" x 7". If 8 Lbs and 35 Lbs consider a flap size around 8" x 11". If your dog is between 35 Lbs and 80 Lbs consider a flap size around 10" x 15". If your dog is over 80 Lbs consider a flap size of 15? x 20?.
Exact Measurement/ Measure your pet's width: Simply open a door the minimum width needed for the widest part of your pet to comfortably walk through, then measure the door opening and add an inch. You can also stand above your pet and use a ruler to measure the widest portion of your pet, then add an inch. It is important to add an inch or so, that way your pet will not rub on the door as they pass through. Determine your pet's height by measuring from the top of your dog's shoulders to it's belly or chest and add 2 inches.