In Ground Stubborn Dog Fence, With Collar, For Pets 8 LB , Comes With 500 Ft Of Wire, 9V Battery, Surge Protector & Flags, Can Expand Up To 25 Acres With Additional Wire. 4 Levels Of Static Correction With Highest Intensity Available For The Most Stubborn Pets. Vibration and Tone Options Included. Anti Linger Prevention, Progressive Run Through Prevention, Low Battery Indicator, Expand to Unlimited Number of Pets With Additional Collar- #PRF-275-19. Uses 9 Volt Battery, Not Included.