Features:Stealth environmental protection: The wires are buried in the ground, do not occupy extra place, do not affect the appearance, and give the dog more freedom.Progressive tone stimulation: When the dog approaches the border, a warning sound is first heard. If the dog continues to approach, the system will make a slight pulse stimulation.Pulse proportional stimulation: Humane high-tech design, the vibration intensity depends on the distance of the dog to the boundary line, the closer the distance, the greater the vibration intensity. There is a also a built-in speed detector, the faster the dog moves, the higher the level of intensity is.Wide range of control: Up to 5,000 square meters, equivalent to a football field. Control range is adjustable by the button on the transmitter.Safe and reliable: Once the wires buried in the ground are harmd, the wire harm indicator will give a loud warning and flash. The light-ning protection device on the converter can avoid light-ning strikes. Specifications:Material: Plastic, MetalColor: BlackStyle: for 1 Dog/ for 2 Dogs/ for 3 DogsSize: Transmitter-Approx.4.53x3.27x1.3inReceiver Collar-Approx.2.64x1.38in, Adjustable Strap Approx.13.4-19.7inWeight: Approx.780g Notes:1.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid.2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Package includes:1 x Indoor Wall-Mounted Transmitter1 x Power Plug1/2/3 x Adjustable Receiver Collar1/2/3 x 6 Volt Battery for Collar1 x Boundary Wire of 300 Metres2 x Extra Metal Contact Points20 x Training Flags1 x Test Bulb4 x Screws1 x User's Manual