Pet Remote Trainer Dog Electric Training Shock & Vibrate Collar 1. Multi-dog training system--Expandable to three-dog operation. 2. Train up to three dogs from the same transmitter.(Purchase extra receivers separately.) 3. Range up to 1000M (on open air). 4. 3 modes for correction and training--Tone, Vibration and stimulation. /99 levels for each model. 5. Free combination among Tone, vibration and stimulation.