Express Trainer Long Range Remote Obedience Trainer is an advanced remote radio dog trainer that quickly teaches dogs multiple behaviors with High Tech Pet's proprietary Command - Tone - Stimulus training system. Three positive training tones may be activated at the collar. These tones are associated with positive commands such as "Sit", "Heel" and "Retrieve". A negative tone is provided to command our dog to cease unwanted behavior such as digging, barking, chewing, etc. The negative tone may be followed by one of four increasingly intense shock levels if the unwanted behavior persists. No other electronic trainer provides such a complete and comprehensive training system. ? mile range. Includes hand-held transmitter, radio collar, short and long hair probes and complete training manual. Receiver collar and transmitter are fully waterproof and operate on built-in rechargeable lithium-ion batteries. Commands up to 3 dogs with additional receiver collars sold separately.