A liner hanger has slips held by a slip body. The system comprises a stem component comprising a anchoring portion and a mounting portion, and a head component having an open channel wherein the open channel is configured to connect to the mounting portion along an assembly axis that is transverse to a longitudinal axis of the stem component. The attaching ring includes a weapon attaching portion, a retaining portion and an extending portion. The center computer 30 distributes the charge amount to management companies on the basis of the charge record. The VTR is only required to record video data intermittently on the magnetic tape and a general home VTR can be adopted as the above VTR, this also prevents the magnetic tape from being damaged.