These are universal pod tapered air filters that have a 42mm opening. They have a ribbed rubber flange that measures about 1-5/8″ across the opening. The pod filter overall dimensions are 2-3/4″ across and 3-1/4″ long. They include a stainless steel clamp so these can be used on a multitude of carbs. These are also a perfect fit for Amal carburetors, commonly found on Triumph, BSA, Norton and other British motorcycles. They also fit Kawasaki KZ440 / KZ750 / KZ900 / KZ1000 along with many other bikes.