The Ferplast Swing 3 Door Extension is an essential module for the Ferplast Swing range of dog and cat doors. Designed to be installed with the smaller pet flap models, such as Swing 1, Swing 3, and Swing 5, this extension is particularly useful for thick doors or walls. Each module adds a depth of 5 cm, allowing you to create a longer passage tunnel suited to your needs. This extension model is specifically recommended for the Ferplast Swing 1 pet flaps, available in various colours, while the larger models, Swing 11 and Swing 15, are already supplied with a tunnel.