The present invention discloses a packet transmission device and a packet transmission system which can realize high-capacity communication. The hand tool comprises a body portion, a stem portion and a bit interface. Any apparatus which accomplishes continuous casting is appropriate for use with the present invention. Through the use of the drive switches for over-driving, initial sense operation can be performed on data line pairs with a voltage having an amplitude larger than a data-line amplitude, allowing implementation of high-speed sense operation. The depression portion spans the full width of sheet media that may be supported in the tray and the second sheet supporting surface lies in the same plane as the first sheet supporting surface. Alignment of the ports of the pistons with their respective recesses permits fluid flow through the tool both when the valve is opened by the lower piston and closed by the upper piston.