Simple installation steps: This can be done on wooden or PVC doors. Adapters required for brick walls, window panes and patio doors Adapts to various climatic conditions: With its weather-resistant strip and enhanced automatic double locking function, the wind or heat stay outside Offer greater freedom to your dog or cat: this allows you to offer maximum freedom to your dog or cat; it is an ideal solution for letting cats and dogs into your home without having to open the door frequently. Your pet will be more independent Simple and practical locking: in addition to being easy to install, this door also allows you to offer maximum freedom to your dog or cat. Resistance: this cat flap is robust and durable, thanks to its hard transparent plastic blade and its high quality durable plastic frame; the door is suitable for most standard walls and doors There are four modes (1) Close the cat flap lock in both directions. (2) means the door opens in both directions. (3) Allow cats to go out, but don't let cats in. (4) Entry is permitted but not exit. Easy to install, simple and generous. Good quality, using ABS material (imported ABS material) Large size, larger size, suitable for many big cats. Size model: (support selection) Size M: Frame size: height 22.3 * width 19.2 * thickness 5.5 cm < li> Door cover size: inner height 15.5cm * inner door width 15cm L size: frame size: height 24 * width 23.5 * thickness 5.5cm Door cover size: inner height 19.5cm * inner door width 17cm Shop Tips: 1. The size is measured manually, please allow the error (1-3 cm). 2. Due to different monitor pixels, there may be color difference, please refer to the actual product.