a base member including an accommodating structure configured to accommodate a power supply, the power supply having a circular cross-section defining a radial direction extending radially from a center axis of the circular cross-section; and

an operating member pivotally coupled to the base member about a pivot axis,

the accommodating structure including a power-supply accommodating space, the accommodating structure being configured for insertion of the power supply into the power-supply accommodating space of the accommodating structure in an insertion direction along the radial direction of the power supply, and the insertion direction is non-parallel to the pivot axis, and

the accommodating structure being configured such that when the power supply is accommodated within the power-supply accommodating space, the center axis of the power supply is non-perpendicular to the pivot axis.