A golf club head comprises a sole, a recessed sole port in the sole; and a rotatably adjustable sole piece adapted to be at least partially received within the sole port and comprising a central body having a plurality of contact surfaces adapted to contact the sole port and being offset from each other along a central axis extending through the central body of the sole piece. A plurality of memory cells have each output coupled to an input terminal of one of the access transistors so that the access transistors share one of the wordlines and are coupled to different bitlines. A rectangular first feedback cavity is in microwave communication with each of the first main-line cavity and the second main-line cavity through the respective sidewall of the first main-line cavity and the second main-line cavity.