Lockable screen doors for dogs and cats! Why be at Fido"s or Fluffy"s mercy whenever they want to go outside or come back in? Simply snap the plastic frames of this easy-to-install large flap door together through the existing screen of your patio door, cut out the screen door, and your dog or cat can easily enter or exit anytime...unless you choose to lock the pet door. This convenient "cat flap" or "doggie door" works with all types of screens, and also can be installed in screened windows between the kitchen and patio as a food and drink pass-through. Make your dog or cat happy with this pet screen door. .