$The Hound Hunter SD-3225 haas a range of up to 2 miles, keeping control of a long-range pursuit is easier than ever. Designed for a wide range of dog handlers including pet owners, obedience trainers, bird hunters, rabbit hunters, and waterfowl hunters. The 4-DOG SD-3225 system is fully customizable, allowing you the flexibility to set 2 or more transmitters to control the same collar receiver.With the introduction of the new HoundHunter model specifically designed for controlling tracking and trailing dogs, you keep the thrill of the chase within your control. The model SD-3225 allows control of up to six dogs from one compact transmitter. The HoundHunter model SD-3225 allows control of up to six dogs by adding SportDOG SDR-AH Add-A-Dog collars.