The H2O 1820 PLUS remote trainer comes with Nick Stimulation, Continuous Stimulation and non-stimulating Positive Vibration. This unit has an 1800 yard (1 mile) range and 16 levels of stimulation. The transmitter and collar unit are completely waterproof. 1800 Yard (1 Mile) Range. Expandable up to 3 dogs with H20 PLUS Add-On Collars. 16 Levels of Intensity adjusted from the Transmitter. "Basic Obedience Training" booklet by George Hickox. Digital Technology to Maximize Power. "Maxx-Range" Internal Collar Antenna System. "Gentle Touch" System Extra Mild Stimulation. Built-In Safety Shut-Off. Rechargeable Ni-MH Battery System. Completely Waterproof Transmitters and Collars.