Kra pipe refers to the hot-state winding formed high-density polyethylene (HDPE) winding structured wall (Type B) pipe. This pipe is made primarily from high-density polyethylene resin, using a hot-state winding forming process, with polypropylene (PP) single-wall corrugated pipe as the supporting structure, resulting in a special structured wall pipe with high external pressure resistance. The pipe's specifications, dimensions, and performance comply with the requirements of the GB/T19472.2-2017 standard.