A device (1) for controlling the rate of flow of a fluid such as fluid which is diverted from a part of a human or animal body. The device comprises: an inlet (2); an outlet (4); and a resistance member (6), operatively connected to the inlet (2) and the outlet (4), the resistance member (6) comprising: a first plate (8), a surface of which comprises a groove which defines a resistance flow channel, an entry of the flow channel being in fluid communication with the inlet (2) and an exit of the flow channel being in fluid communication with the outlet (4); and a second plate (12), the second plate being held in abutment with the grooved surface of the first plate (8) so as to define a resistance (tube 14).