Abstract: A high performance constant velocity universal joint is based on a body which encloses the constant velocity joint components and provides a smooth spherical outer surface. A one-piece semi-rigid plastic boot in the form of a truncated sphere has a smooth internal spherical surface sized to match the outer surface of the body. The plastic of the boot is sufficiently elastic to allow the boot to snap over the body, yet sufficiently resilient to snap the open end closed after the boot is snapped over the body to provide a substantial seal preventing entry of debris under the seal. A retaining ring is positioned on the boot near the truncated end to resist plastic creep which would result in enlarging the opening and allowing debris to enter the seal.