ALEKO TS-DF01 Dog in-Ground Pet Fencing Device with Waterproof Collar Will not hurt your pet, Fits for the dog with weight from 30-100lbs, neck size 1-18 inches Can be expanded for yards up to 5 acres with the purchase of additional wire/ flag kits (sold separately) Audible wire break alarm, Visual wire break alarm, Variable field width control Pet fencing device with pulsed proportional stimulus, Progressive tone stimulus, Low battery consumption Effective, affordable fence keeps your dog safe and secure in your yard, Speed detection anti-run through