The Educator ET-400 one dog system with 3/4 mile range, small receiver for small to medium sized dogs 10 pounds and up with neck size 5 to 22-1/2 inches Includes 1 Biothane dog collar (3/4" wide x 30" long), 1 RX-090 mini receiver (2" long x 1.5" wide x 1" high, 2.4 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