A bellow seal of a fluid dispensing system is disclosed. The bellow seal having a generally circular cross section includes a first end having a first diameter. The bellow seal further includes a second end having a second diameter that is smaller than the first diameter of the first end. The bellow seal further includes a contoured external surface extending between the first end and the second end. The external surface includes a cylindrical portion extending from the first end, an undulating portion, (which includes a convex portion extending from the cylindrical portion and a concave portion extending from the convex portion), and a tapered portion extending from the concave portion to the second end. The bellow seal further includes a flexible region defined between a first point located on the cylindrical portion and a second point located on the concave portion.