The ornamental design for an earinsert for a wireless headset, as shown and described.
FIG. 1 is a perspective view of an ear insert for a wireless headset showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof; a right side elevational view being the same;
FIG. 5 is a top view thereof.
FIG. 6 is a bottom view thereof.
FIG. 7 is a rear perspective view thereof, the undisclosed portions are not part of the claimed design; and,
FIG. 8 is a reference view thereof, where an ear insert for a wireless headset having the subject design is used. The broken line showing in FIG. 8 is for illustrative purpose only and forms no part of the claimed design.