Drainex drainage pipe has an innovative double wall sandwich construction, with a corrugated outer wall and a smooth inner wall. This combines high ring stiffness with excellent flow characteristics. Rows of water in-take slots are symmetrically arranged around the apex of the pipe (240˚- 270˚) with a flow channel at the bottom (120˚- 90˚). The high infiltration area combined with thin inner wall structure ensures optimum water intake. The slots are protected in the valleys of the corrugated structure which reduces the possibility of blockage. The smooth core with an extremely low roughness coefficient results in greater flow rates, allowing the utilisation of smaller diameter pipes. Drainex is manufactured in coils and lengths to the highest quality standards and are joined by push fit couplings.