The ornamental design for a headset, as shown and described.
The FIGURE is a perspective view of a headset showing my new design. The broken line representation and the undisclosed rear forms no part of the claimed design.
CORRECTIVE ASSIGNMENT TO CORRECT THE ASSIGNEE ADDRESS PREVIOUSLY RECORDED ON REEL 034471 FRAME 0075 ASSIGNOR S HEREBY CONFIRMS THE CORRECT ADDRESS IS KEILALAHDENTIE 2-4