This dual pane dual flap Hale pet door fits in a vertical sliding window (aka sash window, double hung window). This unit has an end which telescopes about 1.5 inches to fit into the track just like a window fan or air conditioner. Minimum track thickness must be at least 1" to accomodate the thick...

This dual pane dual flap Hale pet door fits in a vertical sliding window (aka sash window, double hung window). This unit has an end which telescopes about 1.5 inches to fit into the track just like a window fan or air conditioner. Minimum track thickness must be at least 1" to accomodate the thick...