Supply water directly to your plants with 1/4 in. distribution tubing. Attach tubing to the main line to create a feeder line that delivers water to a low-flow, drip-watering device, or use as a main line in a smaller drip system. The quarter-inch tubing, also known as micro tubing or spaghetti tubing, has an outside diameter (OD) of 0.250 in. and internal diameter (ID) of 0.170 in. While other manufacturers use blended recycled material to construct their entire tubing, Raindrip poly tubing is engineered in layers for durability using 100% virgin content for its outer and inner layers, with a middle layer of recycled content.