Got a new dog in the family? Here's an extra collar for your Express Train remote radio dog training system. Express Train 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, Heal and Retrieve. A negative tone is provided to command a 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. One half mile range. Fully waterproof. Operates on a built-in rechargeable lithium-ion battery.