Dellorto 4057 fiber float bowl nut gasket for VHB and early PHF carbs. Guzzi number 13933900, seals bowl nut to the float bowl. ~18 mm ID x 23mm OD. Used on all VHB carburetors on Ambassador, 1969-1971 V750 Special, Eldorado, 850 GT, V7 Sport, 850T, 850T3, Convert, G5, 1000SP, CX100, and early PHF36 carburetors on 850 LeMans. The float bowl nuts that these seal are the smaller ones that use a 14mm wrench to loosen.