of pistons 164 166 stems 168 170 consititute the mechanical contactors of this embodiment and are provided with circumferential grooves 176 178 respectively caps 180 182 seal bores 160 162 from the ambient environment and thereby compress springs 184 186 which bias pistons 164 166 downwards as viewed in fig8 in the biased position grooves 176 178 are out of alignment with passage 158 and fluid cannot pass from the fluid inlet 104 which is connected to a source of fluid pressure to the outlet which is connected to a body requiring fluid pressure such as the floatation bladder mentioned earlier the schematic diagram of fig1 is useful in illustrating the mode of operation of this embodiment wherein as the male part incorporating the pneumatic valve of fig8 is drawn into contact with a female part the mechanical contactors 168 170 are caused to translate upon full penetration the pistons 164 166 are depressed to the extent that grooves 176 178 are aligned with passage 158 this valving action allows fluid flow to inflate the floatation badder as is readily understood finally a less preferred embodiment of a pneumatic valve is shown in the schematic of fig1 fig1 shows a control piston 184 which acts as the single obturator between an inlet 104 and an outlet 106 upon full penetration of a female part by a male part incorporating the valve of fig1 the piston 184 is depressed to such an extent that groove 186 is aligned with a flow.