A reflector clamping member (RCM) for fixating an ultrasound reflector (REF) to a flow conduit insert (FCI) of an ultrasonic flow meter (UFM) is disclosed, the reflector clamping member (RCM) comprising a fixation portion (FXN) for fixating the reflector clamping member (RCM) to the flow conduit insert (FCI) and a flexible portion (FLX) for contacting the ultrasound reflector (REF), wherein the flexible portion (FLX) is adapted for supporting at least one side of the ultrasound reflector (REF) so as to clamp the ultrasound reflector (REF) between the flexible portion (FLX) and the flow conduit insert (FCI) when the reflector clamping member (RCM), the ultrasound reflector (REF), and the flow conduit insert (FCI) are assembled. Also, a flow conduit insert assembly (ASY) comprising such reflector clamping member (RCM), an ultrasonic flow meter (UFM) comprising such reflector clamping member (RCM), and a method of fixating an ultrasound reflector (REF) to a flow conduit insert (FCI) are disclosed.