Abstract: A security bar assembly for an opening includes an elongate bar extending across the opening, and a socket connector assembly at each end of the bar to be secured to the respective side of the opening by means of a fastening accessible only from within the socket. At least one of the latter sockets is provided with an abutment adjacent its outer end extending inwards from the socket into abutting relationship with the bar when the bar is supported in the socket and one end of the bar is provided with retractable pins extending beyond the bar upon insertion into the socket beyond the abutment.