Endura three colorsEndura three colors

Endura Flap Thermo Panel 3e



  • The Thermo-Panel 3e is the best all-around patio panel dog door for sliding glass doors
  • Insulated, dual pane, LoE glass, in sturdy aluminum framing
  • Features safe, energy efficient Endura Flap
  • No tools required for installation, perfect for renters and vacation homes
  • Adjustable heights and custom sizes to fit any sliding glass door




The Endura Flap Thermo Panel IIIe is designed to save energy.  It’s easy to install, and it stops drafts!

***Please measure your sliding glass door/patio door track height before ordering. Measure from the lowest point in your patio panel floor track to the highest point in your patio panel ceiling track.***

Shipping charge on panels are per panel. Panels can only be shipped to Alaska, Hawaii, or Puerto Rico by overnight service. Please call customer service at 800-749-9609 for shipping details.


  • Dual-pane, Low-E glass insulates and filters out heat for energy efficiency.
  • Flap material is a polyolefin-based polymer which is safe for your dogs, cats and the environment. Unlike others flaps it remains flexible in temperatures as low as -40 degrees Fahrenheit.
  • Simple design allows you to easily install and remove your panel as necessary; simply loosen the thumbscrews at the top to release the spring-loaded mechanism and tighten once in place!
  • This panel will not mate with an existing sliding door lock so we include either a C-Clamp Lock for adjustment ranges up to 80 1/4″, or a Foot Lock for panels 80 1/4″ and above. You could also use the old “broomstick in the track” method or a Charley Bar. If your slider is on the outside you would be unable to use any lock besides the Foot Lock. Which can be purchased separately here if your panel height is below 80 1/4.
  • Choose from four different sizes that have a high aspect ratio, meaning they are taller and narrower to better fit more pets.
  • User-adjustable step-over feature allows you to set the height of the flap to best suit your pet. Solid magnet strips along the sides and magnets at the bottom of the flap keep your pet door sealed year round. Magnets are adjustable to make training easier.
  • UV and wind resistant, the Endura Flap has been designed to remain sealed in winds up to 50 mph.
  • Heavy duty aluminum frame provides extreme strength and durability, designed for sliding glass door tracks at least 1” thick.
  • Durable and secure locking cover to close your pet door when necessary; equivalent to 1/16” steel.
  • Three height ranges to fit most sliding glass doors, and if your slider doesn’t fall within these ranges we can custom build one for you!
  • 90 day return policy, and a generous 15 year warranty for your peace of mind.


Flap Size Flap Dimension Step Over Range Overall Panel Width
Small 6″ w x 11″ h 3″-5″ 11 3/8″
Medium 8″ w x 15″ h 3″-7″ 13 3/8″
Large 10″ w x 19″ h 3″-9″ 15 3/8″
Extra Large 12″ w x 23″ h 3″-11″ (ships at 5″) 17 3/8″

How to Measure

Measure your pet’s height from the ground to the tallest point of their back. To measure width, it is best to open a door or block off a space to have your pet walk through. Measure the minimum width required for your pet to comfortably walk through without squeezing!

When selecting a flap, you will need to keep in mind how high off the ground the pet door will be mounted. We call this distance the Step Over. Add the step over to the flap height to determine the height of the top of the flap – this measurement needs to be at least 1″ taller than the height of your pet. Remember that a lower step over is always easier for your pet, especially as they get older! As a benchmark, most dogs will do great with a 3″-5″ step over. It varies based on body type and range of mobility.

What size dog door do I need?

Follow these steps to ensure a safe, comfortable passage :

  1. Measure your pet from feet to shoulder (If you have pets sharing, measure the tallest and the shortest)
  2. The top of the pet door flap should be at least 1 inch above their back
  3. The flap height + Step over = Top of the Flap
  4. Consider how high your pet(s) are comfortable with stepping over
  5. You do not necessarily need a flap size that is the same size as your pet, you can create a “mock” opening to see what your pet is/isn’t comfortable with

Additional information


White, Bronze, Silver

Flap Size

Small, Medium, Large, Extra Large

Track Height

74.75"-77.75", 77.25" – 80.25", 93"-96", Under 74", 80.5" – 93"