Round. Fits many 6" type air cleaners to fmc-508-910, fmc-516-263, Dragtron & Dragtron Star air cleaners. - Height 51mm (2") - Inside diameter 102mm (4") - Outside diameter 137mm (5.375")
Fits: > Most H-D with Keihin butterfly, Bendix & Tillotson carbs with 6" round housings
