These Refill Sprays are designed for use with the Intellipet Citronella Anti-Bark Dog Collars (see item ZW18810 sold separately), Each 2, 4 oz can contains harmless, non-staining citronella-scented spray that is released from the collar when dogs bark, distracting them with a spritz of spray and conditioning them to stop barking, Each refill lasts for approximately 18-23 uses, SKU: PETED8984