4 way interlock: on, off, on/off, lock Four types of cat flaps are locked, you only need to swing out, in and out, fully lock, and easily drive pets in and out. It's time to wait for your pet Glass distribution: Clear design makes your window glass overall quality, best for viewing windows, sliding glass doors, glazing, perfect for all glass adjustments Pets will instantly fall in love with stylish pet flaps Smooth and comfortable: the cat flap consists of two parts Door brush bars prevent door noise, internal rubber ring protects your cat from harm, and the silent action won't scare pets or let the owner let the cat into her litter box DURABLE AND RESILIENT: All cat doors are made of durable plastic that is weather resistant and easy to use Rugged UV-resistant 100% polycarbonate construction ensures a virtually unbreakable dog door Outer size (30*30*4CM) Inner size: 18.5*20.5cm Recommended hole size: 26.7cm round hole diameter Material: PC+ABS Net weight: about 465g