Hamilton 1-Inch Double Thick Safe-Rite Dog Collar with Center Ring The center ring is for the safety of the dog in case of entanglement This collar is not as tight on dog due to the center ring Enables dog to get untangled in branches and limbs and free itself safely When measuring pet's neck or chest to ensure proper and comfortable fit, add 2 inches. When measuring pet's neck or chest to ensure proper and comfortable fit, add 2 inches.