Whiskers & Windows Cat Door for Horizontal Sliding Windows | Great for Cats | Easy Entry and Exit Control | Large Cat Flap, Fits Windows 46"-49" h, White

The Whiskers and Windows Cat Door fits perfectly in window tracks and is easily adjustable to accommodate different sizes with trimming. The product is well-made and easy to install. One issue mentioned was that the flap is tight, but pre-glued foam insulation helped with the problem. There is an adaptor available for sliding glass doors and custom sizes available for non-standard lengths. The lock can be a bit of a pain and the product only comes in black frames, which may not match white frames. Overall, it is a good product from a reliable company that is damage-free and perfect for rentals.