Recommended Dog Breed* examples (Over 6 months) *Cavalier King Charles *Maltese *Scottish Terrier *Jack Russel *Beagle *Kelpie *Staffy *Whippet The extra Barkmate DF112 Fence only collar to suit Barkmate Invisible Dog fence system. This collar is designed for smaller dogs from 4kg in weight. It is water resistant and operated by 6V alkaline battery. This collar is NOT compatible with Barkmate DF212, DF213 Fence system. Â