Micro 1/4″ Tubing: This tubing is available in Polyethylene (PE) or, the more flexible Poly Vinyl Chloride (PVC). Available in 50, 100 and 1000 foot rolls.  1/4″ Tubing is most commonly used as an extension from the distribution (1/2″ or larger) tubing. It is usually connected directly from the emitter or to a DD-C250 which then leads to the drip emitter at the plant source.  1/4″ tubing is not recommend for single runs longer than 20ft.