New AT-219 Remote Control Trainer Electric Dog Shock Collar for 2 Dogs,18 Levels of Progressive Shock + Adjustable Vibration + Adjustable Ultrasound Auto Anti Bark, Rechargeable and Waterproof Environmentally friendly---Rechargeable collar receiver,save?$$$?on buying replaceable batteries 3 Modes?(Vibration+ Ultrasound+ Shock) with 6 Separate or Combination Choices 18?Levels of progressive shock +adjustable vibration + adjustable ultrasound Auto anti-bark. Can let the device do the barking control when the dogs left alone Suitable for healthy dogs of over 6?months old