Knob

FIG. 1 is a top perspective view of an exemplary knob according to a new design; FIG. 2 is a front view thereof; FIG. 3 is a back view thereof; FIG. 4 is a left side view thereof; FIG. 5 is a right side view thereof; FIG. 6 is a top view thereof; FIG. 7 is a bottom view thereof; FIG. 8 is a bottom perspective view thereof; and, FIG. 9 is a section view taken along the reference line 9 - 9 of FIG. 6 . The portions depicted in broken lines form no part of the claimed design.