Dogtra 2502 T&B Train & Beeper. A compact training and beeper unit designed for the discriminating upland hunter. 2-dog system. (Product Group: Remote Training Collars / Remote plus Beeper) The beeper has a 400-yard range and a dual high and low three-level volume adjustment selector A single transmitter controls 2 collars/beepers The unit is fully waterproof The rheostat dial allows for gradual adjustment of stimulation The transmitter has an LCD window that displays the intensity level, along with a three-bar battery life indicator