Dura-Line Smooth Wall HDPE Innerduct Conduit. All Dura-Line smooth wall conduit meets or exceeds applicable industry standards and is manufactured from flexible HDPE for a variety of installation methods (direct burial, HDD, aerial, trench, plow, etc.). Options include co-extruded SILICORE® ULF lining for improved cable pulls, factory pre-installed Bull-Line pull tape (e.g., 1250#), multiple colors (orange commonly used for communications), and multiple SDR/Schedule variants (SDR 9, SDR 11, SDR 13.5, etc.). Distributor pages list the product as available by foot or on reels; configurations and reel put-ups vary by SDR, color, tape and reel size.