Give your small dog the same fence-free security and boundaries large breeds enjoy with PetSafes Elite Little Dog Fence. Strap on the waterproof, ergonomic receiver with reflective collar and your dog can go outside while staying within a set space while you enjoy fenceless freedom. Included wire surrounds up to 1/3 if ab acre. Four adjustable levels of static correction condition your dog to stay within the invisible fence. Run-Through Prevention Correction mode increases the collars potency each time your dog tests the boundary line. Tone-only mode alerts your pet with sound when they get close the buried wire. For dogs 5 lbs. and up. Powered by PetSafes replaceable RFA-188 battery (included). Collar fits neck sizes from 6 to 16 in circumference. Comes with transmitter and power adapter, test light tool, 50 boundary flags, 500 ft. of wire, wire nuts, gel-filled capsules, mounting bracket. Expandable to 25 acres with addtional wire and an unlimited amount of collars. Type: Pet Containment Systems.