Dual drain pipe with a smooth interior reduces the risk of drain clogging. Particles attach themselves not as easy on the smooth inside and with good water flow through the tubes even cathartic!
Pecora SDP produced in PE in sizes 50/60 and 83/100mm the coil and outside dimensions (OD) 75/63, 110/97 and 160/140mm in straight lengths. For inside dimensions (ID) produced in 200 and 250mm. Standard lengths of straight length of drain pipe is 6 meters.