A protective tubing assembly having male and female connectors integrally formed along its exterior surface and an asymmetrical cross-section with additional wall thickness in the non-connector cross section regions is provided by the present invention. Cooperating, substantially flat exterior bearing surfaces may also be formed along the exterior surface of the tubing. The tubing can be wound into coiled alignment with the male and female connectors securing adjacent coils together, and the additional wall thickness regions in the asymmetrical cross-sectional reducing unwanted twisting of the tubing that would otherwise lead to individual coils rising from their original, substantially planar coiled alignment. An extrusion manufacturing process with special inner and outer dies is also provided.