White 5 yr old Patio Pacific pet door installs and removes in seconds. Double pane glass fits sliding doors. Patio door then locks in place by use of a dowel placed along bottom track of door. Fits doors 74 3/4" to 77 3/4" in height. Extra flap for pet entrance included. Pet dr is 6"W x 11" H
Cost about $320 new. Asking $80 obo cash only
See website to verify it fits your patio door and how to install. http://www.petdoors.com/quick-panel-iii-the-endura-flap-patio-pet-door.html