Microtubing
Microtubing or spaghetti tubing is a very fine plastic tubing used in drip irrigation, typically in gardens and greenhouses, with a small inside diameter which may be 0.05" or smaller.
Microtubing is inserted directly into the supply tubing, usually without any fittings. The flow is regulated by the inside diameter of the tube and the length of tubing used. The smaller the diameter and the longer the tube, the greater the friction loss, thus reducing the pressure and flow. The end of the tube may have a plastic or lead weight to hold the tube in a pot.
Microtubing is one of the oldest products made for drip irrigation, having been manufactured for about fifty years. It has largely been replaced by other drip irrigation products such as emitters, microsprinklers, and drip tape.