Dogtra YS300 Dog Collar recognizes bark sound vs surrounding noise 7 levels of correctdion 2 hour quick charge Bark Recognition that distinguishes a dogs barking from its surrounding ambient hoises. Non-electrical stimulation vibration warning prior to the stimulation, 6 intensity levels (2-7) for a wide variety of dispositions, Fits dogs as small as 10 lbs (receiver weight: 4.0 ounces), 2 hour rapid charge Lithium Polymer batteries