The V10 trainer is purchased as a single dog unit but can easily be used for dogs. The Dog 2 collar can be simply programmed to the users handset either at the time of purchase or as a later addition. The Vibration Trainer has 10 levels of variable vibration plus an audible (tone) signal. Each collar can be programmed individually to retain each dog’s training level. The easy to use handset allows the user to swap quickly between Dog 1 and Dog 2 and the handset will show both dog’s distance from the user as well as their individual training level and collar status.