Our Dogtra 2300 Expandable is a long time tried and true dependable remote e-collar. Designed for advanced training, this is a favorite with competitive trainers, hunters and police K-9 professionals. This low to high power system has a full range of 127 stimulation levels to match all dog temperaments. It has expandability allowing you to train two dogs simultaneously with purchase of the additional receiver-collar. With a full 3/4 mile range, an LCD display on the transmitter and waterproof design, it is ideal for all types of terrain and training conditions.