NeoPaw Dog No Bark Training Collar with Remote Wireless Dog Fence Containment System Covers Up to 2 Acres Ultrasonic Dog Repellent Portable Transmitter - with built-in rechargeable battery, the transmitter can be used for almost 18 hours after fully charged Wireless Boundary - safely keep your pets in the yard with no digging and no wires to bury Adjustable Boundary - covers up to 2 acres Waterproof Receiver - for pets over 5 lb. with neck sizes from 6 - 28 inches Please don't put the receiver collar on your dog when the system is tested. Your pet may receive an unintended correction