An e-collar designed for pet obedience training, K9 or sport dog training, DOGTRA 1902S TRAINING SYSTEM is the perfect unit for you. It has a ¾ mile range with a precise stimulation level (0-127). It uses low to high power output with Nick, Constant and vibration only for the stimulation type. It also has a LCD screen. Both collar/reciever and transmitter are fully waterproof and uses a Li-Polymer 2 hour quick charge batteries. This is highly recommended for dogs weighing 20 lbs. or more. This unit can train up to two dogs.