4-dog; Designed for beagler/hound trainers; Low to high-end power; 1-mile range; 8 nick and 8 constant levels; waterproof; rechargeable Designed for the Beagle and Hound owners who need a dependable long-range training collar to control a number of dogs in the field at once. The 1800 Series is a reasonably-priced single or multi-dog unit that offers sixteen levels of stimulation with a selector style intensity control. (8 Nick and 8 Constant modes). Features a waterproof receiver/transmitter along with long-lasting rechargeable Ni-MH batteries, and a one-mile plus range. These features, along with industry-leading durability, make the 1800 Series Trainer... The leader of the pack!