12” key tensioner-style stainless steel band for 12-inch dust collection hoses and 12” inch dust vent hoses. #2 Phillips head or 5/16” drive screw mechanism ensures a good repair with a tight fit. 9/16” inch wide stainless-steel band fits hose diameters from 10.375 inch diameter up to 13.5 inches. Pack of 4. Clamps should be doubled up on both ends of a hose. One with the key/screw on the left, and one on the right. This ensures uniform tension and a tight connection in applications where heat and vibration are present.