Hunter emitters apply water slowly and directly at the plant to ensure every drop is put to efficient use. They come in three convenient styles including self-piercing barb, 10/ 32 threaded, and ½" (15mm) female thread. The barb and 10/ 32 thread models are available in 2, 4, 8, 15, and 23 l/hr models, and the ½" (15mm) female threaded models come in 4 and 8 l/hr.