The invention relates to a valve, in particular for use in hydraulic circuits, comprising a valve body (4) which is designed as a cartridge, can be integrated into a housing (6) that has fluid connections (8), and can be fixed in the housing by means of a securing device (20, 26, 28). The invention is characterized in that the securing device has at least one blocking element (20) in the form of a separate component which can be found between the valve body (4) and the housing (6), said blocking element having blocking surfaces that can be moved relative to the longitudinal axis (18) of the valve body (4) between an assembly position which allows the valve body (4) to be inserted into the housing (6) and a blocking position in which the blocking surfaces secure the valve body in an assembly position preferably with zero backlash by bearing against retaining surfaces (26, 28) of the housing (6) and the valve body (4).