PetSafe Cat Flap for doors as well as in windows and walls with a 4-way security system. This glass-compatible cat flap from PetSafe is also suitable for medium-sized cats. You can install the cat flap in both doors and windows and walls. The PetSafe cat flap features a transparent flap and a manual 4-way security system. Suitable for cats up to 7 kg and a maximum shoulder height of 15 cm.