Sportdog in-ground rechargeable fence system FEATURES:-1000ft of wire, 100 flags, & 1 collar receiver are included to keep your dog contained in a yard up to1.3 acres-Wire-break transmitter alarm alerts you to possible problems w/ the boundary wire-Anti-linger feature prevents dog from running down the battery in the warning zone Other Features: 7 levels of static stimulation , vibration/tone options, waterproof design, includes 1000 feet of wire and 100 boundary flags, expands to any number of dogs with purchase of additional collars, expands up to 100 acres with purchase of adntl wire and flag kits