This is the replacement flap and the surrounding plastic frame for the Ideal pet door that comes in the Ideal Fast Fit and Ideal Fast Sash pet doors.
Ideal dog door replacement flaps are available separately if your plastic frame is still in good shape. Ideal has discontinued the old style flaps and frames. The new style has a round logo in the flap a few inches from the top. The older style usually says "Made in USA" right on the flap and has the size printed right on it. The parts are NOT interchangeable. If you have an older Ideal pet door, Fast Fit, or Fast Sash it will have to be replaced.