Featuring an easy-to-read OLED screen, you can view the selected dog, static stimulation level, and mode, as well as battery status, with just a glance. This, combined with large plus/minus buttons to easily toggle among dogs and stim levels, makes the SD-875 especially suited for multi-dog hunting situations. With SportDOG® Add-A-Dog® Collar Receivers (sold separately), the remote trainer can be expanded to control up to 3 dogs at once. And both the handheld/transmitter and receiver/collar are fully waterproof/submersible. 10 levels of both continuous and momentary static stimulation, as well as vibration and tone options in select modes, allow you to customize this system to fit any situation or dog’s temperament.