The Ideal e-Cat Storm Door Cat Door - sold separately - uses an E-Sensor collar
to ensure that only your pet has access to the door. Replace a lost collar or
allow additional pets access to the door with the Ideal E-Sensor Break Away
Key Collar For e-Cat Cat Door.
Designed for safety and security the collar controls the door ensuring that
no other critters - or burglars - enter your home. Includes 9-volt battery.