COVONO Wireless Dog Fence GPS,Invisible Fence 15lbs 120lbs Dogs (Electric Dog Fence,Pet Containment System,Waterproof Rechargeable Collar,Shock Tone Correction) Size:For 1 Dog With the purchase of additional With the purchase of additional compatible COVONO receivers 3 acre to 496 acres Rechargeable and waterproof collar with beep shock 3 levels of static correction to match dogs with different sensitivity A full stimulation lasts 20 seconds at a time The stimulation was limited to 3 times to prevent overstimulation All functions are integrated in the collar then your dog will be back easy to carry and use Low battery indicator is available For dogs from 15 pounds to 120 pounds 90 days return period and lifetime warranty How it works