CAT DOOR SIZE: The measurement of external diameter is 11.8 inches. The length and width of flap door is 8.5 * 7.2 inches. The thickness for the whole door measures 1.65 inches. It fits all kinds of cats and small dogs. PVC MATERIAL: Due to the PVC plastic of this cat door, it is possessed of a lot of outstanding features, such as lightweight, toughness, durability, non-toxic and fire resistance. Moreover, the see-through flap door makes it easy for cats and small dogs to feel at easy when going through. PLUNGER LOCKER: One of the most outstanding features about this cat door is that it has a manual plunger locker for safety protection. Therefore, it keeps your pets safe and the thieves won’t easily sneak into your house.