An emitter unit adapted to be integrally bonded to an internal surface of a conduit (30). The emitter comprises a housing (1), a housing inlet (13) adapted to communicate with an interior of the conduit (30), a housing outlet (26) adapted to communicate with a conduit outlet; said housing (1) being constituted by a receiving member (2) and a cover member (3) adapted to be coupled together to form a box like structure; elongated grooves (11, 24) formed respectively in inner surfaces of both said members (2, 3); a resiliently flexible membrane (4) mounted in said housing (1) and overlying said grooves (11, 24) so as to define therewith component flow restricting flowpaths which communicate via a communicating aperture (28) formed in said membrane (4), a flowpath inlet (11a) of one of said component flowpaths communicating with said housing inlet (13); a flowpath outlet (24a) of the other of said component flowpaths communicating with said housing outlet (26).
