Screw in style gas cap tank set, 3.5 gallon. All stock and aftermarket products sold for Fat Bob gas tanks will fit, and this tank has one 13/16 inch external thread fuel valve connection. Gas tanks are unpainted. Fits Big Twin 4 speed frames 1936-1984 (except Softail). We recommend that you use (#05419) fuel tank liner and prep kit after pressure testing your tank. This can be found in the Accessories section. OEM# 61219-83