The outlet points from which gases & vacuum are drawn are of self sealing type and have non-interchangeable outlet fittings. The supply is established simply by inserting the appropriate safety key plug into the orifice of the outlet point and pressing it home until it locks in position. To break the connection, the milled collar round the orifice is rotated a few degrees to the right, when the safety key plug is automatically elected and the gas flow is cut off.
