K-Rain's ProSeries 150 Valves offer the irrigation professional a wide array of features and benefits. The 1 in. (2,5 cm) valve has a removable metering pin and external bleed screw promoting easy maintenance and manual operation. Manual External Bleed Screw The 1 in., 1-1/2 in. and 2 in. (2,5, 3,8 and 5 cm) models feature a removable external bleed screw and metering pin to simplify cleaning and maintenance. With the External Bleed Screw, manual operation during start up is easy.