The D. T. Systems Micro-iDT Plus Training Collar uses the Maxx-Range™ internal collar antenna system to transmit 16 levels of nick and continuous positive vibration stimulation to train your dog. The lightweight collar is rechargeable and waterproof, while the weatherproof transmitter features no-slip rubber coating and an easy-to-use stimulation dial for 1-hand operation. The 900-yard range allows for household and field use, and the system can be expanded to accommodate up to 3 dogs (additional collars sold separately).