The present specification discloses tetrahydroindolone derivatives or analogues and methods for treating cognitiveattention deficit disorders using such tetrahydroindolone derivatives and analogues. The distal ends of the guide rods include a visual distinction that is seen peripherally by the golfer. By virtue of this configuration, a cut surface having a better surface roughness as compared to that obtained conventionally can be obtained in cutting of a soft material such as wood by use of a circular saw. The diodes have second electrodes connected to a corresponding one of the at least one power supply unit and the redundant power supply unit. The sustain driver includes an inductor into which a current flows in the same direction during the first period and the second period.