A slider device for selectively interlocking and unlocking complementary profiles of opposing tracks of a plastic zipper closure; the slider device comprising: (a) a top member with an opening end and an opposite closing end; (b) pair of spaced legs (96, 97) depending from the top member; the spaced legs defining an open volume therebetween to allow for passage of the tracks therethrough and with the legs having terminal ends (101, 102) straddling the tracks; (c) the top member having an internal surface within the open volume between the legs; the internal surface including at least a first region and a second region; (i) the first region extending from the closing end partially along the internal surface of the top member; and (ii) the second region being between the first region and the opening end; (iii) the first region extending at a greater distance from the terminal ends of the spaced legs than the second region; (d) internal surfaces (112, 113) spaced sufficiently close together to press the profiles into interlocking relationship as the slider is moved in a closing direction along the zipper closure leading with the opening end and trailing with the closing end; (e) a separator plow extending from the second region of the top member into the open volume between the legs; the separator plow being positioned to wedge between opposing tracks and unlock the profiles as the slider device is moved in an opening direction along the zipper closure leading with the closing end and trailing with the opening end; and (f) the second region of the top member including an engagement surface positioned to strike an end stop on at least one end of the zipper closure. (a) a top member with an opening end and an opposite closing end; (b) pair of spaced legs (96, 97) depending from the top member; the spaced legs defining an open volume therebetween to allow for passage of the tracks therethrough and with the legs having terminal ends (101, 102) straddling the tracks; (c) the top member having an internal surface within the open volume between the legs; the internal surface including at least a first region and a second region; (i) the first region extending from the closing end partially along the internal surface of the top member; and (ii) the second region being between the first region and the opening end; (iii) the first region extending at a greater distance from the terminal ends of the spaced legs than the second region; (i) the first region extending from the closing end partially along the internal surface of the top member; and (ii) the second region being between the first region and the opening end; (iii) the first region extending at a greater distance from the terminal ends of the spaced legs than the second region; (d) internal surfaces (112, 113) spaced sufficiently close together to press the profiles into interlocking relationship as the slider is moved in a closing direction along the zipper closure leading with the opening end and trailing with the closing end; (e) a separator plow extending from the second region of the top member into the open volume between the legs; the separator plow being positioned to wedge between opposing tracks and unlock the profiles as the slider device is moved in an opening direction along the zipper closure leading with the closing end and trailing with the opening end; and (f) the second region of the top member including an engagement surface positioned to strike an end stop on at least one end of the zipper closure.