US Patent 7150244 Window adaptable pet door

The present invention relates to a pet door suitable for use in a window, and more particularly to a pet door having a substantially planar profile. In at least one embodiment, the pet door includes a frame which is cooperative with stationary side panels. The frame carries a moveable door through which an animal may enter and exit. Moveable side panels are housed within, and extendible from, the stationary side panels for securing the pet door within a window frame.