FIG. 1 is a left side elevational view of a handpiece for massage or therapy, according to our new design; FIG. 2 is a right side elevational view thereof; FIG. 3 is a front elevational view thereof; FIG. 4 is a rear elevational view thereof; FIG. 5 is a top plan view thereof; FIG. 6 is a bottom plan view thereof; and, FIG. 7 is a left bottom perspective view thereof.