A slider device having contoured top and sidewalls is disclosed for use with a resealable package. In a first embodiment, the slider device includes an engagement structure for engaging and interlocking first and second closure profiles of a resealable closure mechanism. The engagement structure includes a first protrusion and a second protrusion depending from the top wall of the slider device for engaging first and second closure profiles of a resealable closure mechanism. The first and second protrusions selectively open and close the resealable closure mechanism as the slider device is moved from a first position to a second position. In a second embodiment, a slider device is disclosed having first and second slide channels that engage first and second closure profiles. The first and second slide channels selectively open and close the resealable closure mechanism as the slider device is moved from a first position to a second position.