Barks are detected via an internal microphone and each bark triggers a mist of spray, which is unpleasant, but harmless for your dog. Choose from lemon or lavender scents. Each can contains about 25 sprays. The collar is water-resistant and the long-life battery will last for approximately 3 years of use or 4 years in stand-by.This Ultra lightweight collar weighs only 1.48 ounces and is automatic (no adjustment required). Includes one can of spray (2.63 fl oz) in your choice of scent. The turquoise nylon strap is adjustable to fit neck sizes from 5.9" to 21.6".