A fastener (300) for holding two panels together, including: a grommet (12) having a flange and an opening there through; an elongated pin (410) characterized by a pin longitudinal axis (442) along its length; a receptacle (404) having a central opening and female threads (602); an insert member (406) having two ramped bayonet slot arrangements (562) and male threads (560); and a pin receptacle (612) formed partly by a recess (610) in the female threads and partly in the insert member when the receptacle and the insert member align. In a first position (500) the pin does not occupy the recess in the female threads, thereby permitting relative rotation between the receptacle and the insert member. In a second position (640) the pin occupies the recess, thereby preventing the relative rotation between the receptacle and the insert member.