Abstract: Irrigation drip tubing including an outer tubular member having an inside wall and an outside wall and an inner tubular member having a repetitious pattern of inlet apertures, crests and roots. The crests engage the inside wall of an outer tubular member in a liquid-tight manner. The roots form conduits which connect to form oppositely directed passageways through which the fluid flows resulting in a pressure drop that drastically reduces the fluid volume flow. The inlet apertures in the inner tubular member provide for fluid communication between the inside of the inner tubular member and the passageway. Removable bosses may optionally cover outlet apertures. If used, the bosses project outwardly from the outside wall of the outer tubular member and are located periodically along the length of the tubing.