Our most versatile collar, with more levels of correction and patented bark detection technology. Eighteen levels of correction. Collar adjusts to neck sizes from 6 to 28 inches. No programming required. Automatically adjusts to deter barking. Dual sensor technology for Perfect Bark™ detection every time. Low battery warning light. The lightest bark collar available – only 1.5 ounces. Exclusive Lifetime Limited Warranty.