An outflow-purgable and adjustable emitter (1) is described for use in micro-irrigation systems. The emitter (1) comprises； a hollow body (2) defining a flow channel having a fluid inlet, which channel continues towards a fluid outflow in the form of a resilient slitted-aperture (10), which aperture provides a resistance to the flow of fluid from the body (2), the said body having one or more radially displaced projections (7) from the outer surface of the body and adjusting means (5) in mechanical association with the body and assembled to move relative to the body to selectively engage with the projections (7), and with said resilient slitted-aperture (10) also being selectively deformable. An end cap of otherwise similar construction convertible to such an emitter by provision of a slit is also described.
