PetSafe Small White Plastic Frame Pet Door with Locking Panel is for pets up to 15 lbs. This easy-to Install pet door fits doors from 3/8" to 2" thick, with a flap opening of 5-1/8"W x 8-1/4"H and a cut-out size of 6-3/8"W x 10-1/8"H. The durable plastic frame includes a closing panel for added security, making it ideal for storm doors.