The Deluxe Bark collar is the most advanced bark control collar ever made! Some bark collars detect barking with a microphone and activate on sound; these can be set off by other noises or by another dog's bark. Some bark collars use only vibration' these can be set off my motion or jostling. The patented Perfect Bark (tm) Technology simultaneously senses both sound and vibration, and only a combination of the two will trigger the electronic correction. Note: The image represents both the Deluxe Bark Collar (bottom) and the regular Standard Bark Collar (top). The Standard Bark Collar (#PSSBC6) is sold separately.