Extended Gas Tank - Smooth-Top - Twin-Cap - Sportster Extended design of these tanks allows the lines of the tank to flow into the lines of the seat for a great custom look, Tanks have cutout in rear for seat nose (some seats may need to be shortened), 2" longer than a standard QuickBob tank, Includes necessary mounting brackets, 3.9-gallon capacity, Utilizes a 22 mm petcock, When installed on '92 and later models and the OEM continuous venting system is eliminated or disconnected, do NOT reuse your stock vented cap. Stock vented cap should be replaced with earlier version of the screw-type caps.