HDPE pipe for the duration of extrusion. The HDPE materials is coming from the heater, into your die, then in to the cooling tank. This Acu-Electricity conduit pipe is co-extruded - black within with a thin orange jacket, to designate ability cables. Also known as "hole flanging", hollow cavities in https://zionxtiwl.goabroadblog.com/28841371/new-step-by-step-map-for-aluminium-extrusion