DIG B221B 1 GPH Pressure Compensating PC Drip Emitter (10 Pack), Black Available in three colors so that it is easy to identify flow rate Ideal uses on slopes, oddly shaped areas, sites with high winds and long run. Pressure compensation feature enables the use of longer laterals under a wide range of pressures Turbulent flow through a large labyrinth water passage and floating diaphragm help prevent clogging Resistant to chemicals and fertilizers used in landscape application