Back in the early 1950's Stelling and Helling produced an air cleaner cover very similar to this one. O'Brien Truckers has modified the adaptor plate that comes inside this cover so that once you buy it you can use it with one or two 4 BBL carbs or two or three 1 BBL's or 2 BBL's. Being a universal cover, we sell cotton gauze washable lifetime elements and cast aluminum bases for one, two and four barrel carbs to give you a complete traditional setup just the way they did it in the '50's. This 15" air cleaner cover comes complete with an adaptor plate, two neoprene / stainless steel washers and two stainless steel button head bolts ready to cover elements and bases you have or the elements and bases of your choice that you purchase.. This cover measures 15 1/2" L x 7 1/2" W x 3 1/4" T with 1 3/4" element or 4 1/4" T with 2 1/2" element.