
Endura Flap Installation Adapters
Thermo Panel Adapters for Monorail Doors
Creates a secure, custom-fit channel for monorail sliding doors, improving panel stability, reducing movement, and delivering a cleaner, more integrated finish
Regular priceFrom $116.00 CADUnit price
Frequently Asked Questions
What is a monorail door, and how do I know if I need the adapter?
A monorail sliding glass door has a single raised center track rather than two separate channels. Typically the monorail is square or rectangular in shape, typically about 3/4" tall and 3/4" wide. On these doors, a standard patio insert has too much room to shift or tilt. The Monorail Adapter creates a defined channel that holds your Thermo Panel firmly in place. If your slider rides on one center rail, you likely need the adapter.
My panel shifts or tilts in the track. Will the monorail adapter fix that?
Yes, for raise monorail track systems. The Monorail Adapter is designed to stop that side-to-side movement. It seats the panel into a stable channel so the installation feels intentional rather than improvised, and it helps keep the panel aligned consistently over time.
If your pet door panel shifts instead because you have a very wide track, or a completely flat track like some storm doors, or certain brands, feature, you may instead want to use shims or a bracket to secure the pet door frame in place.
Can the Endura Flap Thermo Panel work with a monorail vinyl slider?
In most cases, yes, paired with the Monorail Adapter. Because monorail tracks vary in shape, send us a photo of your door's center rail and we'll confirm fit before you order.
My panel came up a little short. Can I make up the difference?
Yes. The Panel and Window Height Extension adds 3/8" to a sliding glass door or window panel, which is ideal for correcting small measurement errors. Add the extension to close the gap for a secure, weather-tight fit.
Which panels does the height extension fit?
The height and sash width extension is compatible with all Endura Flap pet door for sliding glass doors or windows. It comes in a variety of sizes to fit your specific door type. Note that the pet doors that install horizontally in a window will instead use the extension on the side, to provide a slightly greater overall width.
Does the extension work for both height and sash width?
Yes. The extension is designed for the Endura Flap Thermo Panel and Thermo Sash, adding height to a sliding door panel or width to a sash window installation for a seamless, secure fit.
Can I use the monorail adapter and a height extension together?
Yes. Many installations use both: the Monorail Adapter to stabilize the panel in a single-rail track, and the height extension to fill any gap at the top. Together they give you a snug, stable fit in tricky openings.
How do I attach the monorail adapter to my door?
The Monorail Adapter mounts to the panel to form the supporting channel. You will need to drill through the pet door panel in order to secure the monorail adapter in place, using the provided hardware. We do not pre-drill holes in your pet door, as we find that sometimes, once you have the pet door in place, the monorail adapter may be unnecessary and can be safely returned. Pre-drilling would leave holes in the pet door frame for no useful reason.