An electroacoustic transducer serving as a speaker or a microphone is reduced in size and weight and is capable of generating sound with relatively high sound pressure. The tower loop is firmly supported in the raised position by the linear actuators to provide a proper attachment for towing enthusiasts, and is lowered to allow the water craft to be stored in a normal height garage structure. A feature vector extraction unit multi-divides the multifocus iris image sequence extracted in the eye image pretreatment unit. Movement between the different modes can be effected by rotating the device between a dual portrait orientation, corresponding to the first mode, and a dual landscape orientation, corresponding to the second mode. If the first gray code value equals the second gray code value, the output of the comparator is provided to a logic block that produces a status flag in the correct clock domain.