A panel mount connector (2) comprises a panel mount component (4) and a movable component (8). The panel mount connector (4) can be mounted to a panel (4) by a combined sealing and provisional mounting ring (10). The movable connector part (8) comprises a terminal receiving housing (16) and a bayonet type rotatable locking ring (18) having a first axial position allowing mounting of a rubber boot (20) to the housing (16), the locking ring (18) retractable to a second position partially extending over the rubber boot (20) in order to prevent it from being accidentally pulled off the housing (16). The connectors (8 and 4) can then be mated together by aligning keying means of the housing (16) with corresponding keying means of the panel connector housing (12), axially moving the housings together, and then rotating the bayonet type locking ring (18) until an end position whereby the sealing ring is compressed between a flange (114) of the locking ring and the panel (6) for sealing therebetween.