Transport water directly to your plants with 1/4 in. distribution tubing. Branch off the main line to create a feeder line to supply water to a low-flow, drip-watering device, or use as a main line in a smaller drip system. The 1/4 in. tubing, also known as micro tubing or spaghetti tubing, has a 0.250 in. outside diameter (OD) and 0.170 in. internal diameter (ID).