Abstract: The present invention provides an improved, self sealing, female pneumatic coupling of the type that releasably engages a grooved nipple attached to a pneumatic tool or fixture. The conventional elements of the female coupling include a ball bearing latch that prevents removal of the grooved nipple when activated and a locking sleeve to activate the ball bearing latch. The improvement of the present invention, in a preferred embodiment, includes locking sleeve having separable segments to form a set of first, second and third combination locking tumblers each of annular configuration. A set of numbers is provided on the outer periphery of each of the tumblers. Each of the tumblers must be rotated so that a selected number thereof is opposite to an index before the locking sleeve can be moved to deactivate the ball bearing latch.