The Boss ET-802 two dog system with 1 mile range, large receiver for large dogs 20 pounds and larger with neck size 6 to 22 inches Includes 2 Biothane dog collars (1" wide x 30" long), 2 RX-120 large receivers (2.7" long x 1.7" wide x 1.2" high, 4 oz.) and 1 ergonomic "stopwatch" transmitter (2.75" diameter x 1.2" thick x 4.6" high) well-suited for small hands or in situations where discretion is important Delivers a tapping sensation similar to vibration, but more intense, making it an effective addition to the stimulation A Pavlovian tone feature provides an effective addition to the stimulation User-selected stimulation levels range from 1 to 100 with additional boost stimulus selectable from 1 to 60