Material The pet door that can control the direction of entry and exit is made of ABS plastic, corrosion-resistant, smooth and durable. Please choose the size that suits your pet. 4-way switch mode The cat door with lock has 4 switch modes. The cats pet door can be adjusted by labelled red and green switches. It can be set to open, enter only, exit only or fully lock, easy to adjust and make you Pets get in and out easily Easy installation Can be easily installed on doors, windows, cabinets, panels, walls, etc. Intimate design The transparent flip cover allows pets to see through the door. A must-have item for pet lovers. Owning it can reduce the time it takes you to open and close the door for your pet. SIZE Small External dimensions: height 20CM* width 19.2CM* thickness 1.5CM (suitable for installing glass doors and windows) Inner size: inner height 15.5CM* inner door width 15CM medium External dimensions: height 20CM* width 19.2CM* thickness 5CM Inner size: inner height 16CM* inner door width 15CM Use weight range: less than 14 pounds (regular recommendation) waist circumference less than 40cm large External dimensions: height 25CM* width 23.5CM* thickness 5.5CM Inner size: inner height 19CM* inner door width 18CM Use weight range: less than 16 pounds (regular recommendation) waist circumference less than 60cm extra large External dimensions: height 29cm* width 25cm* thickness 5.5cm Inner size: height 22cm* inner door width 20cm