Dura-Line Smoothwall HDPE conduit (Smooth Wall) — flexible HDPE conduit/innerduct designed for telecommunications and underground applications. Smoothwall is available with optional SILICORE® ULF lining and multiple SDR/wall thickness options; available sizes from 1/2" to 6" and colors including orange. Factory pre-installed Bull-Line pull tape (e.g., 1,250 lb) is available; meets multiple industry standards (ASTM, NEMA, UL, Bellcore). (Data assembled from Dura-Line family technical documents and distributor product pages; manufacturer site access for MCN-specific page was blocked.)