Holster Attachment

FIG. 1 is a front perspective view of a holster attachment, showing our new design; FIG. 2 is a back view; FIG. 3 is a front view; FIG. 4 is a top view; FIG. 5 is a bottom view; FIG. 6 is a first side view; and, FIG. 7 is a second side view. The broken lines show portions of the holster attachment that form no part of the claimed design.