Motor driven vertically-sliding door is activated by MS-4 ultrasonic collar;Directional sensing system opens the door only when your pet is on a direct approach, not when he is just wandering by or sleeping next to the door;4-way access control lets you select from In Only, Out Only, Full Access or Closed & Locked;Wind and weatherproof with airtight seal; automatic deadbolt locking adds a level of security higher than any other pet door;Panel size: 12-1/4 by 16-inch for pets up to 100-pound, Kindly refer user manual and instruction video for reference.