An oil pan is provided for an internal combustion engine. A test sound generation unit generates a test sound including a probe and a masker, and outputs the test sound from a test sound output unit. These organic-inorganic composites can be constructed from the nano- to the macro-scale depending on the size of the fibrous protein fusion domain used. The coordinate determining unit determines three-dimensional coordinates of each point on the detected outline. When pressed against the clip assembly by a user, the liquid tank is fastened by the clip assembly and thus retained in position. It provides for support of the toe and rotation of the foot so that the user can walk with the foot in a normal position for walking.