the mounting flange the socket barrel 13 carries seven male pins not shown in an array per sae standard j650 the seven pins extend into the inside of the socket sleeve 15 and form a socket into which can be plugged an end of the electrical cable connecting the tractor to a trailer the socket is closeable by a spring loaded cap 19 hinged from the rear face 31 of the socket mounting flange 18 the socket barrel 13 is generally circular and carries seven male terminals 14 terminals 14 can be the opposite end of the pins accessible in socket sleeve 15 and so terminals 14 can be arranged in an array like that of the terminal array according to sae standard j650 the barrel 13 is adapted to mate with a sleeve of a corresponding electrical plug 60 the electrical plug 60 comprises a generally round body 16 optionally formed in the shape of an l shaped elbow having a first end 40 and a second end 42 the first end 40 carries seven female terminals 17 that extend into the body 16 in an array which matches the array of the socket terminals 14 the body 16 is made of an elastomeric material and includes an annular sleeve 20 which axially extends from the first end.