Handpiece

FIG. 1 is a front perspective view of a handpiece showing the claimed design; FIG. 2 is a front view thereof; FIG. 3 is a rear 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; and, FIG. 7 is a bottom view thereof. The dash dash broken lines in the figures illustrate portions of the handpiece that form no part of the claimed design.