Ensure continuous effectiveness of your PetSafe bark control collar with the PetSafe Citronella Spray Refill. Formulated with natural citronella, this refill cartridge releases a burst of pleasant fragrance to deter unwanted barking. Keep your pet's training regimen on track and enjoy a quieter environment with this convenient refill option from PetSafe. Refill cartridges release bursts of citronella scent to deter barking behavior. All-natural citronella formula for a safe and effective deterrent. Easy-to-install refill for continuous training and bark control.