water sealing properties as obtained by using the elastomeric sleeve 44 above described may also be realized by tightly securing an elastomeric layer 60 in sealing relationship immediately below the opening 32 39 in the jack body 24 39 as shown in fig5 the layer 60 has a protrusion 62 with a preferably conical guideway 64 formed on its external surface to guide the center conductor 30 in the mating plug connector 28 for engaging the split pin 38 39 a thin wall 66 remains in the layer 60 immediately above the split pin 38 39 so that a watertight seal exists at the opening 32 39 even before the center conductor 30 punctures the thin wall 66 the protrusion 62 may project out above the top wall of the jack body 24 39 for a distance d so as to enable a watertight compression seal to be effected between the protrusion 62 and the inside face of plug connector 28 when connector 28 is mated to the jack body 24 39 for a standard type 34 f 34 jack body 24 39 it has been found that the protrusion 62 should preferably extend about 0 5 millimeters above the top of the jack in order to ensure that the above mentioned compression seal is in fact achieved an insulative support sleeve 68 is dimensionally formed to maintain a pressure contact with the underside of the layer 60 when the support sleeve 68 is operatively disposed within the jack body 24 39 the layer 60 is thereby squeeze fitted between the top end of the support sleeve 68.