Techniques are described for providing load balancing functionality among multiple computing nodes. A control gate of the control transistor comprises an n-type polycrystal silicon film and is formed over a gate insulative film comprising a silicon oxide film. The first inductive storage element is coupled between the first node and the first battery. Additionally, a small size antenna such as a chip ceramic antenna is used exclusively for RFID reception, and the RFID reception antenna is also used as a mobile communication antenna. The locking pin is flexible for bending at least in one plane coincident with the longitudinal axis of the locking pin, and is preferably also longitudinally elastic. The training content helps to guide the user through the practice session.