D.T. SYSTEMS H2O Receiver Collar Waist Wader High performance 9 Axis Rate High performance 9 Axis Rate Gyro Compass provides the autopilot with excellent steering response Manufacturer Part No : PTS 2 The H2O Add On Collar unit can be added to any existing H2O 1800 PLUS series training system (excluding Beeper models) to expand your unit up to a 3 dog system Key Features:• Digital Technology• Adds to any H2O 1800 PLUS series training system(excluding Beeper models)• Replaces any lost or damaged H2O 1800 seriestraining system (excluding Beeper models)• Up to 1800 yard (1 mile) range• Lightweight and waterproof• MAXX Range Internal Antenna System• Rechargeable Ni MH batteries• Built in safety shut off system• Available Limited Lifetime WarrantyPackage Contents:• 1 x Collar Unit w Green collar belt• Double jack Cable