... !* Can be used as 1 dog, 2 dog or even 3 dog training system (extra collars needed ... high-quality Aetertek 216S-550W for 1 dog remote dog training system features 7 levels of shock, ... used for many different training purposes, such as barking, digging, jumping on people, running away, chewing ... after day without problems. Aetertek dog shock collar anti bark dog collar pet collar ,for 1 dog , 550M range