The Sonic Yard Barrier emits a powerful sonic blast triggered by your pet's ultrasonic collar to keep doggie and kitty out of the garden, away from trash cans, away from the pool, and out of ALL "Off-Limits" areas. This Electronic Fence System for dogs and cats uses painless sound, not electric shock to keep your pet out of flower beds, gardens, off the porch, away from pools, ponds, trash cans or any other off limits area. The Yard Barrier's heavy-duty outdoor receiver unit may be placed anywhere that is "off limits" to pets. The lightweight electronic pet collar sends an ultrasonic signal that triggers a loud audible sonic blast at the receiver unit when the pet approaches. Dogs and cats are easily trained to Stay Away! The electronic transmitting collar and the receiver are water resistant and weatherproof. The Yard Barrier's ultrasonic system is superior to cheaper infrared devices because it allows people to come and go without triggering the alarm. The sonic alarm is triggered only by your pet's individual electronic transmitting collar. Range is fully adjustable from 1 to 35 feet. Extra Transmitter Collars may be used to restrict additional pets and extra Yard Barriers may be used to restrict additional areas. Features: Uses sound - not shock Keeps pets out of restricted outdoor areas One collar powers yard barrier, sound barrier and power pet door Add as many yard barriers as needed to keep pets out of multiple restricted areas Add as many yard extra transmitter collars to keep additional pets out of restricted areas Includes one collar battery and one receiver battery (each lasts about 2 months)