The Educator ET-802 1 mile remote training system is loaded with unique features, making it the most humane and effective trainer available. The transmitter offers user-selectable stimulation levels from 1 to 100. A "lock and set" feature prevents accidental overstimulation by allowing the user to lock in a desired level. A blue LCD display shows the stimulation level at all times. For situations when you really need to get your dogs attention, theres an additional boost feature, which provides more powerful stimulation. Set the boost level from 1 to 60, depending on the dogs temperament. Smaller dogs typically respond to a boost of 1 to 20, while bigger, more stubborn dogs may require a boost of 20 to 60. With its ergonomic "stopwatch" design, you dont even have to look at the transmitter, allowing you to watch your dog at all times. The transmitter also controls a tracking light which allows the user to flash or continuously light up the collar receiver for locating a dog after dark. A beeper can be turned on to help locate a lost transmitter. The waterproof transmitter even floats, so dont worry if you drop it in the lake! The medium/large receiver on the collar (2.7"x1.7"x1.2", 4 oz) utilizes a unique technology that provides very clean and reliable stimulation without the normal head jerking often found with other training collars. The receiver delivers a tapping sensation which is similar to vibration, but more intense, making it an effective addition to the stimulation. For dogs 20 pounds and larger. Transmitter and receiver include rechargeable Li-Polymer batteries. Package includes transmitter with lanyard, two receivers, two 1" x 30" collars, battery charger, test light, 5/8 and 3/4 inch contact points, contact point installation tool, carrying case and owner's manual.