The Dogtra E-Fence 3500 is an effective underground containment system with rechargeable a collar for mild to stubborn dogs. Set custom boundaries around your property that allows your dog to be safe in your yard! Installation:Follow these simple four steps: Step 1 - Map out the installation plan Step 2 - Set up the transmitter Step 3 - Place the underground wire Step 4 - Place boundary flags and train your dog to avoid them Fence Wire - The fence wire must make a continuous loop around your property for your system to operate. The signal is delivered from the terminal of the transmitter, through the fence wire, back to the other terminal on the transmitter. When this is accomplished, the wire continuity light will emit a constant red indicator. The wire should be buried approximately 4-6 inches into the ground, or deep enough to protect it from being damaged by any machinery or dug up by your dog. The wire does not have to be buried in order to work.Features: 2-Hour Rapid Charge BatteriesFor Dogs 15 pounds and up Non-Stimulating High Performance Pager provides vibration before stimulationVibration Only setting for timid dogs 8 Low to Medium Stimulation Levels Ultra-Compact Receiver/CollarFully Waterproof Receiver/Collar40-Acre Maximum Area CoverageWire Break Light and Alarm 1-Year Warranty What's in the Box:Wall Mounting TransmitterWaterproof ReceiverTransmitter Power AdapterBattery Charger for Receiver500 ft. 16 Gauge Underground Fence WireTraining Flags (50 each)Waterproof Splices (4 each)Test LightGround Wire (Dark Green)Transmitter Mounting Screws (2 ea) & plastic anchors (2 ea)Plastic Training ProbesOwner's Manual & Training Manual How Much Wire Do You Need? Acres Feet of Wire 1/3 500 1/2 700 1 1000 2 1400 3 1700 4 2000 5 2200 6 2400 7 2600 8 2800 9 3000 10 3200 12 3500 14 3700 16 4000 18 4200 4500 25 5000