Smooth Wall HDPE continuous length conduit. High-density polyethylene (HDPE) resin. Smooth Wall HDPE Innerduct is made to Industry Standards for Communications Applications. It can be installed using open trench methods, HDD (Horizontal Directional Drilled), plowed, or pulled into conduit. Under Eastern Quality Assurance System Certification. Available in Orange, White, Yellow, Blue, Green, Red, Black and Gray.