faces receptacle shell 10 includes a non engaging end 16 rearwardly of flange 18 and threads 15 on the forward mating end 14 receptacle connector 10 is mounted in panel 30 such that the receptacle non engaging end 16 extends from front face 32 rearwardly and through opening 36 mounting flange 18 abutting front face 32 and forward mating end 14 extending outwardly from the panel for mating engagement with forward mating end 24 of plug shell 20 the means 40 for releasably coupling plug shell 10 to receptacle 20 are as shown in the aforementioned u s pat no 4 279 458 and the specification and drawings of which being incorporated herein by reference comprise a plurality of segmented housings 44 having a thread portion 45 thereon adapted to engage with receptacle shell thread 15 an operating sleeve 42 circumposed around plug shell 20 and segmented housings 44 and slidably disposed to cam the segmented housings radially outward from engagement with thread 15 on the receptacle shell and a plurality of springs 66 positioned in a housing 46 to bias operating sleeve 42 into its forward connected position operating sleeve 42 includes an exterior forward end portion or marginal annulus 41 of cylindrical shape and a generally transverse end face 43 segmented housings 44 have an segment end face 47 when mated an exposed area 50 see fig2 exists at the forward end of the releasing connector locally of the segmented housings and the operating sleeve as well as around the threads on the receptacle shell radially between operating sleeve 42 and segment end faces 47 around the receptacle shell.