The ET-402 Educator is the 2-Dog version of the ET-400, and like it's 1-Dog counterpart, the ET-402 employs our proprietary ""blunt"" stimulation making it the most humane and effective dog training collar available. Loaded with unique features, including ""lock and set"" stimulation levels from 1 to 100, and the ability to set a boost level from 1 to 60, independently for each dog, the ET-402 allows the user to tailor the stimulation to each dog's temperament. Alternate stimulation options include vibration and tone. The night tracking light can be set to flashing or solid which is especially convenient in the ET-402 2-Dog system. The ET-402 will turn a pair of smart stubborn dogs into a couple of geniuses. 100% Satisfaction Guaranteed. Proudly assembled in the USA.