Abstract: A stroking constant velocity universal joint has a seal boot produced from a thermoplastic elastomer. The seal boot has a large diameter skirt at one end that attaches the seal boot to the universal joint housing and a small diameter ring at an opposite end that attaches the seal boot to a drive shaft associated with the universal joint. The seal boot has a generally cylindrical bellows section that comprises a plurality of serially arranged convolutes integrally connected to the skirt by a conical wall. The bellows section has a maximum diameter that is substantially less than the diameter of the skirt. An intermediate biconic section is integrally attached to the bellows section. It has a maximum diameter that is substantially less than the diameter of the skirt and a root-to-root length that is substantially greater than the root-to-root length of any individual convolute of the bellows section. A single convolute interconnects the biconic section and the small diameter ring.