<p>The invention is for a threaded fastener (10) having a coded drive formation in the form of at least one of a plurality of sockets (16) and a plurality of spigots (116) extending parallel to and spaced about a thread axis (10.2) of the threaded fastener. The coded drive formation is engageable only by a mating drive formation in the form of a plurality of spigots and sockets of a matched key (20) member.</p>
