HDPE pipe in the course of extrusion. The HDPE material is coming within the heater, in to the die, then in the cooling tank. This Acu-Power conduit pipe is co-extruded - black within with a skinny orange jacket, to designate electric power cables. Also referred to as "gap flanging", hollow https://alexistkkao.humor-blog.com/28760066/not-known-details-about-aluminium-design