The Dogtra 1902S e-collar is a 2-dog version of the 1900S, a high output unit of choice for serious amateurs and award winning professional trainers in pet obedience, hunting, competition trials, and K-9. The durable 1902S e-collar features a 3/4-mile range (1200 metres), and is fully waterproof. The receivers have a unique modern design that lets the collar strap wrap around the receiver and your dog's neck for enhanced comfort and seamless appearance. The Dogtra 1902S receivers output low-high stimulation from 0-127 levels, a wide range of stimulation that will fit any dog's personality from mild to most stubborn. Using a patented Rheostat intensity dial, the gradual and precise stimulation control is displayed on the illuminated LCD screen on the handheld transmitter.