![[photo] Top view of the Lockable Cat Flap for Side Sliding Windows](/v/vspfiles/assets/images/ideal_top_425.jpg)
The top spring-loaded adjusting section of the Side Sliding Window pet door appears
as an "H" piece when viewed from the side. The overall width of this piece is
13/16" (Will fit into most any sliding window track).
The spring-loaded adjustment provides for a 2 1/2" range for proper fitting into
your opening. Most top tracks in sliding windows do not have any center
rails, however, if you do have this feature then the top section can
straddle any rail at the top 5/8" wide or narrower.
The spring-loaded top is secured with 2 thumbscrew locks, accessible from
inside the house only, someone from the exterior of the house would not be able
to compress or remove the unit.