FAST-FLAP Cat Door Window Insert with Locking Flap. 30"-36" FAST-FLAP! The portable cat door for your window! Easy to use! No Cutting! No Screws! No Installation! Simply place unit into window! American Made with 100% Recycled Material Durable Weather-Proof PVC plastic. White in color This window unit is portable. Easily moves to any location. Adjusts to fit most windows. Please see sizing details below.