Give your pet freedom to roam with the High Tech Pet Products MS-5 Waterproof Microsonic Collar for HTP Power Pet Doors. Combing a good ol’ fashioned love of pets with superior technology, this collar works with the High Tech Pets Automatic Door. While traditional dog doors leave your home vulnerable to intruders, this collar allows the door to remain locked tight until your pet is ready to go out. Emitting a directional ultrasonic code, it gives your pet access to the backyard when he needs it, while keeping your home safe and sealed tight. And the ultra-rugged design can withstand the most active pets!