The Original & Best Selling Cat Door Window - Often imitated but never replicated, Cat Flap Fever has built premium custom-made windows for many thousands of delighted customers. Eco-Friendly Insulated Protection – Custom-fit ¼-inch window pet door insert blocks drafts and retains warmth. Premium foam and brush weatherstripping seal out heat, cold air, rain, and snow. Secure Smart Access – Choose magnetic, 4-way, or microchip locks that recognize up to 30 pets. Stops strays while letting your own in and out safely. Tool-Free Setup for Renters & Homeowners – Installs and removes in under two minutes. No drilling or hardware. Ideal for apartments, condos, and seasonal homes. Made in Georgia, USA – Handcrafted from premium materials for year-round strength. Designed to withstand temperature swings without warping or cracking. Top-Rated Customer Service - We are committed to getting you the best cat door, and will work closely with you to ensure your complete satisfaction. Your happiness is our top priority! Give your cats and small dogs safe, independent access with a custom-fit window pet door from Cat Flap Fever. Designed for sliding and vertical windows, this removable insert installs in minutes without tools or permanent changes, making it perfect for renters, RV travelers, and homeowners alike. Choose from microchip, magnetic, or 4-way locking flap options to control who comes and goes — the microchip model even allows entry for your pets only, keeping neighborhood animals out. A clear plexiglass base suits shorter windows, while the PVC version adds durability for wider spans. Every insert is handcrafted in the USA from weather-sealed materials that help block drafts, moisture, and pests while providing a secure, comfortable passage for your pets. Upgrade your home with a door that combines freedom for them, and peace of mind for you.