You'll need a cat flap installer for installing a pet door in your uPVC or glass panel. They can also help with more advanced models like microchip pet flaps. DIY attempts to install a pet flap often lead to problems like draughts or low energy efficiency. Professional tradespeople can help https://catflapinstall69666.blogdomago.com/29899685/adding-a-cat-flap-to-your-bifold-doors