An apparatus for punching holes in a casing comprises an elongate casing extending between first and second ends having a plurality of punches adapted to be selectably extended therefrom, the casing having a piston cavity therein, the first end of the casing being in fluidic communication with a pressurized fluid source, a slidable piston contained within the cavity separating the cavity into extension and retraction cavities wherein the extension cavity is operable to pressurize a rear surface of the plurality of punches and the retraction cavity is operable to pressurize a front surface of the plurality of punches and a valve assembly adapted to selectably connect the pressurized fluid source with the extension or retraction cavities so as to extend or retract the punches.