The IUC-4100 and IUC-4200 in-ground pet fencing systems set a new standard in pet containment technology. The difference is in the sleek, streamlined comfortable collar – 30% smaller and lighter than other containment receivers. Fence off areas that are off-limits such as pools, flowerbeds and playgrounds.When your dog approaches the buried wire, a radio signal tells the dog’s collar to administer a warning tone followed by harmless yet effective stimulation. Twisted wire from the system’s control center to the boundary allows your pet to pass safely over. Exclusive run-through prevention automatically deters your pet from challenging the system by increasing the stimulation the closer your dog goes to the boundary. Easy self-installation. Buried wire determines your pet free area. Your pet’s training collar will remind him to move away from the boundary wire into the safety of your yard. UltraSmart In-Ground Pet Fencing (IUC-4100) Features:Sleek, streamlined comfortable collar — 30% smaller and lighter than other containment receivers.Innotek’s exclusive ReadyTest(tm) produces a brief pleasant clicking from the collar to assure you of perfect collar fitThe collar automatically checks itself to ensure everything is working properly every time the collar is put on. A green light indicates the system status is normal and flashes red if there is a problem. A battery status light on the collar indicates a full, half and low charge on the battery.Waterproof — Collar and transmitter stand up to rough punishment, even submerged in water.The new, rechargeable lithium ion batteries charge in only two hours and maintain their charge for weeks at a time.Patented Run-Through Prevention (correction level automatically increases as your pet approaches the boundary) and timeout between corrections help your dog learn limits quickly and safely.Recommended for pets 6 mont