The invention provides a copolymer rubber excellent in processability in kneading and processability in extrusion; rubber compositions containing the rubber; and crosslinked moldings of the compositions excellent in sealing properties and shape retention. The mounting base includes a shaft portion that uniformly tapers from a mounting end portion to a projecting end portion. The great difference in speed between the propeller shaft and the turbine output shaft results in a compact PMA which provides significant electrical power output. Accordingly, a user may intuitively recognize a location of icon and effectively move a location of icon.