Endura Flap Cat Door for Horizontal Sliding Windows
- Removable panel with built-in cat door fits into a horizontal sliding window track
- Durable, aluminum frame and pet door flaps made to withstand extreme weather
- Made with Low-E glass to improve energy efficiency
- Quick and easy installation
- Need a different size? Check out this product's custom options

Product Details
The Endura Flap Cat Door for Horizontal Sliding Windows is made to fit into the existing track of your side-to-side sliding window. It installs in a matter of minutes with a spring-loaded design to safely secure into your sliding window track without any permanent alterations (perfect for renters). The removable panel comes with a C-clamp lock, draft stopper, and weather stripping. It features Low-E glass that is UV and infrared-resistant for maximum insulation value. The flexible flap is lined with adjustable magnets to resist heavy wind and extreme temperatures.
The panels have a 3" spring-loaded height adjustment, so if you have a 48" track, for example, the panel you choose will adjust from 46" - 49" inches. Need a different size? Check out our custom sizing options.
Features:
- Aluminum frame designed to fit into a window track width of at least 1" thick
- Comes with a C-clamp locking option, draft stopper and weather stripping for security and insulation of flap opening
- Low-E glass allows natural light to enter while blocking out unwanted UV rays and infrared light
- Flap remains flexible in -40 degrees
- Fahrenheit temperatures and stays sealed in 50mph winds
- Magnetic sealing closure resists heavy winds/storms
- Flap swings on a rod at the top, avoiding breakage
- Includes a sturdy locking cover
Benefits:
- Removable panel benefits all owners, especially renters.
- Don't need to make any permanent alterations to window
- Available in white, bronze, or brushed aluminum to match your window frame
- Locking cover prevents pets from leaving the house when you want to keep them inside
- Made with durable, long-lasting materials
Size Chart
- Endura Flap Cat Door for Horizontal Sliding Windows6”w x 11”h
Flap Dimensions:
6"w x 11"h
The entry way your dog goes through.Overall Panel Width
11 1/4"
How wide your panel is.


Step-Over Height
3”
The distance from the bottom of the panel to the bottom of your flap.Flap Size | Flap Dimension | Step Over | Overall Panel Width | Recommended Pet Height |
---|---|---|---|---|
Small | 6" w x 11" h | 3" | 11 1/4" | 9" - 15" |
Track Height Adjustment Range is the measurement of your window height from the lowest point of your track to the highest point. Review our Track Measuring Guide for more information. The Endura Flap Cat Door for Horizontal Sliding Windows comes in two adjustable ranges:
- 34"-37"
- 46"-49"
If your measured track height does not fall within one of the ranges above, we can make a custom height. Custom height option may take up to 4 weeks to special order the glass and build the panel. If your measured track height is near the bottom of the adjustment range then you should review A Note of Caution.
Find The Best Pet Door Size For My Pet

A
Pet Height: inches
B
Pet Width: inches
Installation Instructions

Parts
- 1 Horizontal Window Pet Door
- 1 Foam Weather Strip
- 1 Center Post Weather Seal Draft Stopper
- 1 Clamp Lock
- Screwdriver
Tools
- Scissors
- Flathead Screwdriver
Please read instructions & notes thoroughly before installation.
Step 1 Release Spring Mechanism

- Loosen the height adjustment locks at the top of the pet panel with the screwdriver. This allows the spring mechanism to move freely up and down.
Step 2 Check Panel Fit

- To insert the panel into the top track, push up against the spring mechanism and swing the bottom of the panel up and over the threshold. Seat the panel on top of the small guide rail in the track.
Step 3 Apply Weather-stripping

- Once you’re sure the panel fits, remove it from the frame and lay it on its side on the ground.
- Apply the foam weather-stripping by peeling back the paper and exposing the adhesive. Unroll it along the edge of the panel, pressing to ensure it adheres. Install on both sides, trim to fit with scissors.
Step 4 Install Center Post Weather Seal



- The center post weather seal strip (draft stopper) should be installed on the inside of the home. It can be installed on either the back edge of the sliding window panel (Figure A) or the leading edge of the stationary panel (Figure B).
- Place the panel back into the window, then tighten the height adjustment locks to lock it in place. Installation complete!
LOCK DETAILS
Since you likely can no longer use your window’s original lock, we have provided you with an alternative locking method to keep your home secure.
Installing the window clamp: This clamp has a screw that tightens by hand to prevent the sliding door from moving beyond the clamp’s placement. For doors manufactured with the glass slider on the inside track, the lock can usually be installed on the door’s raised track.

If you aren’t able to use the lock that comes with the panel: A great alternative to locking your sliding glass door is a Charley bar or dowel in the track. Both work off the same concept - they block the slider from opening. When engaged you cannot pull the sliding door away from the pet door panel.
Videos
How to Adjust the Magnet Strength on an Endura Flap
FAQ
How easy is this to install? The spring loaded design makes installation of the cat door panel very easy. Once it is in place you can't remove it from the outside either, so it's safe and secure. |
How do I measure to make sure that it fits? You will need to open the window and measure from the deepest down inside the bottom of the track and all the way up into the track at the top. You will also need to measure how wide the track is, since the panel is 1" thick your track has to have at least that width to be able to accommodate it. |
What do I do if none of these door sizes will fit my window? If none of the size options will work with your window, you can get a custom cat door. |
How strong is the seal on the pet door flap? The magnets are stronger than your typical off the shelf pet door, so they will have to push the flap a bit harder to get it open. You can adjust the magnets in the beginning for training purposes by reducing their strengths, however you will lose some of the sealing power. |
Is this just for cats? Small dogs can also use the flap, as long as they can comfortably make it through a 6"w by 11"h opening. |
Does this keep out drafts? This flap seals extremely well so it is great if you are looking for energy efficiency. |
How much does shipping cost? Shipping is calculated at checkout. |
Warranty
Endura Flap products have a lifetime warranty against defects in materials and workmanship under standard regular use. Damage caused by not using the product as intended, improper installation, and chewing is not covered under this warranty.
Customer Reviews

Size Chart
- Endura Flap Cat Door for Horizontal Sliding Windows6”w x 11”h
Flap Dimensions:
6"w x 11"h
The entry way your dog goes through.Overall Panel Width
11 1/4"
How wide your panel is.


Step-Over Height
3”
The distance from the bottom of the panel to the bottom of your flap.Flap Size | Flap Dimension | Step Over | Overall Panel Width | Recommended Pet Height |
---|---|---|---|---|
Small | 6" w x 11" h | 3" | 11 1/4" | 9" - 15" |
Track Height Adjustment Range is the measurement of your window height from the lowest point of your track to the highest point. Review our Track Measuring Guide for more information. The Endura Flap Cat Door for Horizontal Sliding Windows comes in two adjustable ranges:
- 34"-37"
- 46"-49"
If your measured track height does not fall within one of the ranges above, we can make a custom height. Custom height option may take up to 4 weeks to special order the glass and build the panel. If your measured track height is near the bottom of the adjustment range then you should review A Note of Caution.
Find The Best Pet Door Size For My Pet

A
Pet Height: inches
B
Pet Width: inches
Installation Instructions

Parts
- 1 Horizontal Window Pet Door
- 1 Foam Weather Strip
- 1 Center Post Weather Seal Draft Stopper
- 1 Clamp Lock
- Screwdriver
Tools
- Scissors
- Flathead Screwdriver
Please read instructions & notes thoroughly before installation.
Step 1 Release Spring Mechanism

- Loosen the height adjustment locks at the top of the pet panel with the screwdriver. This allows the spring mechanism to move freely up and down.
Step 2 Check Panel Fit

- To insert the panel into the top track, push up against the spring mechanism and swing the bottom of the panel up and over the threshold. Seat the panel on top of the small guide rail in the track.
Step 3 Apply Weather-stripping

- Once you’re sure the panel fits, remove it from the frame and lay it on its side on the ground.
- Apply the foam weather-stripping by peeling back the paper and exposing the adhesive. Unroll it along the edge of the panel, pressing to ensure it adheres. Install on both sides, trim to fit with scissors.
Step 4 Install Center Post Weather Seal



- The center post weather seal strip (draft stopper) should be installed on the inside of the home. It can be installed on either the back edge of the sliding window panel (Figure A) or the leading edge of the stationary panel (Figure B).
- Place the panel back into the window, then tighten the height adjustment locks to lock it in place. Installation complete!
LOCK DETAILS
Since you likely can no longer use your window’s original lock, we have provided you with an alternative locking method to keep your home secure.
Installing the window clamp: This clamp has a screw that tightens by hand to prevent the sliding door from moving beyond the clamp’s placement. For doors manufactured with the glass slider on the inside track, the lock can usually be installed on the door’s raised track.

If you aren’t able to use the lock that comes with the panel: A great alternative to locking your sliding glass door is a Charley bar or dowel in the track. Both work off the same concept - they block the slider from opening. When engaged you cannot pull the sliding door away from the pet door panel.
Videos
How to Adjust the Magnet Strength on an Endura Flap
FAQ
How easy is this to install? The spring loaded design makes installation of the cat door panel very easy. Once it is in place you can't remove it from the outside either, so it's safe and secure. |
How do I measure to make sure that it fits? You will need to open the window and measure from the deepest down inside the bottom of the track and all the way up into the track at the top. You will also need to measure how wide the track is, since the panel is 1" thick your track has to have at least that width to be able to accommodate it. |
What do I do if none of these door sizes will fit my window? If none of the size options will work with your window, you can get a custom cat door. |
How strong is the seal on the pet door flap? The magnets are stronger than your typical off the shelf pet door, so they will have to push the flap a bit harder to get it open. You can adjust the magnets in the beginning for training purposes by reducing their strengths, however you will lose some of the sealing power. |
Is this just for cats? Small dogs can also use the flap, as long as they can comfortably make it through a 6"w by 11"h opening. |
Does this keep out drafts? This flap seals extremely well so it is great if you are looking for energy efficiency. |
How much does shipping cost? Shipping is calculated at checkout. |
Warranty
Endura Flap products have a lifetime warranty against defects in materials and workmanship under standard regular use. Damage caused by not using the product as intended, improper installation, and chewing is not covered under this warranty.
- Reviews
- Questions


Excellent Choice for Windows (Staff Review)
This panel is an excellent choice for installing a cat door in your window. Highly insulating flap and comes with weatherstripping to prevent any drafts.

Great quality, one door to rule them all
Hesitated purchasing this and spent years with a mediocre plastic door from a big box store, finally pulled the trigger and am more than satisfied with the quality construction of this and the ease of installation. Only regret is I didn’t buy sooner.