This is a PetSafe Elite Little Dog Citronells Spray Pet Bark Control Collar Pet Safe. The PetSafe? Elite Little Dog Spray Bark Control Collar effectively deters barking when it is worn. The Deluxe Bark Control Collar has a unique patented sensor that provides the most reliable bark detection available. The Deluxe Bark Control Collar uses both vibration and sound sensors (patented Dual Detection) to discriminate each bark from other external noises. A burst of unscented spray is emitted to deter barking only if both the vibration from vocal chords and the sound from the bark match the same criteria.