Conventional boom designs trap air in the boom causing a delay from the close signal to when spray actually stops. Pentair’s Hypro® Express nozzle body end caps include a passive feature that eliminates the trapped air by allowing the air to escape through the nozzle body. When the boom is completely filled with liquid, the nozzle body’s diaphragm check valve's (DCV) activation time is greatly improved by as much as 85%. The Express nozzle body end cap supports today’s practice of Precision Agriculture by enabling standard nozzle bodies to have much quicker reaction times in response to GPS boom shut-off control signals, turning off spray quickly and decisively on overlaps, end rows, and boundary areas.