Esky 100LV Rechargeable Remote Control Dog Training Collar For One to Two Dogs Provides a professional 100 level shock and 100 level Vibration with Rechargeable LCD digital remote control electric training Collar Rechargeable LCD digital remote control electric training collar remote control electric shock devices Convenience of easy-to-read LCD screen shows the stimulation level. Over 3,000 different identity codes to prevent conflicts with other e-collars. The system can be used for 1 or 2 receivers.(the additional receiver must be the same type as your previous one and purchased from us)