A flow control device is provided for regulating the flow of fluid from a container. An exemplary control mechanism includes an inner cap member, an overcap member, and a ball captured therebetween. The overcap member is adapted for axial translation relative to the inner cap member, thereby facilitating one-handed manipulation. Adapters may be provided to facilitate mounting of the disclosed flow control device relative to containers of differing geometry. A releasable locking mechanism may be provided to prevent the flow control device from becoming inadvertently operational.
