The PetSafe Extreme Weather Pet Door (Pets 15 - 100 lbs) is unique among pet doors in as much it is the first ever door to include a three flap design. The inner and outer flaps are made from a traditional Smokey vinyl type material and are held in place with screws across the top of the flap.

The third (middle) flap is made from an insulating material and is of a yellowish gold color and is designed to help provide a greater degree of energy saving all year round, this in turn could translate into saving money on your annual utility bills. 
The extreme Weather flap has a pleating on the edges of the inner & outer flaps to help maintain a tighter seal as the flap contract in the cold weather.  The flaps include a magnet running the full width of the flap on there bottom these magnets help keep the flaps in place during wind weather.

The locking cover is a snap-on weather shield which is locked in place from the front; this means you do not have to worry about lockout hitting the door handles.

Features:

• 3-flap system offers protection from extreme heat, cold, drafts, insects, or driving rain.
• Maximum energy efficiency is 3.5 times higher over single-flap doors.
• Color: White.
• Snap-on weather cover for added insulation.
• Fits door thickness 1 1/2" to 2".
• Dimensions - 7 5/8" x 11 1/8".
• Flap Opening - 5 1/8" x 7 5/8".
• Great for pets up to 15lbs.
• Durable plastic frame