How It Works: A radio signal travels from the Fence Transmitter through a buried wire, marking the boundaries you wish to set for your dog. Your dog wears a Receiver Collar that detects the signal at the boundary. As your dog approaches the boundary, the receiver issues a warning tone. If he proceeds further, he receives a safe but startling Static Correction. While harmless, the correction will persuade him to stay in the containment area you’ve established. Boundary flags are a temporary visual aid for your pet; remove them after training. This PetSafe® In-Ground Fence™ has been proven safe, comfortable, and effective for pets over 3.6 kg (8 lbs). Features • Lightweight Receiver with adjustable collar • Complete system for up to 1/3 acre (13 ares) • System is expandable and will cover up to 10 acres (400 ares) with the purchase of additional Wire and Flag kits System Includes: • Transmitter with Power Adapter • UltraLight™ Receiver with adjustable collar for neck sizes from 15 cm - 71 cm (6” - 28”) • Operating and Training Guide • 150 m (500 ft) of Wire and 50 Flags • Test Light Tool • Battery (RFA-67D-11)