Would never buy this again....it randomly sprayed citronella with or without any sound initiation and the spray did nothing to deter our Aussie Blue Heeler from barking. The spray unit is also a bit bulky and our dog is slender...uncertain if this would be appropriate for any small dog. You also have to ensure that their fur is not obstructing the spray unit in any way or it will not work appropriately. Our dog has medium shag hair length around her neck, so this provided yet another obstacle when applying her collar. Ugh...too much work and no reward.