The top of the 900 Series Dual Pane / Dual Flap patio Insert has a spring loaded adjustment section. This section has a flat surface as shown in the image (left).
The very top of your sliding door track must be at least 1 1/8" wide for an accurate fit. These inserts are installed with hardware for permanent fit.
Note: The main body of the patio insert is 7/8" thick
The Bottom section of the 900 Series Patio Insert has a 5/16" wide groove that allows for the unit to sit on top of the center rail that is often found in the center of the sliding door track (Bottom track).
If you have a center rail wider than 5/16" then this unit may not fit properly. The overall track on the floor of your sliding doors must be at least 3/4" wide for a proper fit.
Complete hardware is included for installation. Please see the Install Instructions for complete info prior to purchase.