Abstract: A downhole tool is provided suitable for multiple setting and unsetting operations in a well bore during a single trip. The downhole tool is suspended in the wellbore from a tubing string, and is activated by dropping a metal ball which plugs the passageway through the tubing string, such that tubing pressure may thereafter be increased to activate the downhole tool. A sleeve is axially movable within a control sub from a ball stop position to a ball release position, and has a cylindrical-shaped interior surface with a diameter only slightly greater than the ball. Collet fingers carried on the sleeve are radially movable from an inward position to an outward position to stop or release the ball as a function of the axial position of the sleeve.