FIG. 1 is a front view of a slider showing our new design; FIG. 2 is a right side view thereof; FIG. 3 is a back view thereof; FIG. 4 is a left side view thereof; FIG. 5 is a top view thereof; FIG. 6 is a bottom view thereof; FIG. 7 is a front-right-bottom perspective view thereof; and, FIG. 8 is a front-right-top perspective view thereof.