High-Density Polyethylene (HDPE) Telecommunication Corrugated Ducts are engineered to protect and manage telecommunication cables in underground installations. Their corrugated exterior provides enhanced strength and flexibility, while the smooth interior facilitates easy cable. Premier Corrugated HDPE is manufactured from High Density Polyethylene (HDPE) and is intended to be placed inside of existing innerduct. It's ideal for pulls under 1000 ft. and is designed to reduce surface contact when pulling cable. This lightweight product offers maximum flexibility, and allows. 1" PVDF Plenum Rated Fiber Innerduct Snap Coupling (for F1-11437 and F1-11437S only). Corrugated, smooth or split wall types. They are typically buried, and then the cables are air-blown, jetted, pulled or pushed into the duct.