Dogtra 1902NCP FieldStar Remote Training Collar 2-Dog System Precise stimulation level (0-27), 1/2 mile range 'Nick", "Constant" and non-stimulating pager/vibration, Rechargeable Ni-MH batteries, Fully waterproof collar/receiver and transmitter, LCD screen displays exact level of stimulation even in dark or low light conditions, Three bar battery life indicator