Embodiments relate to a method of manufacturing a transistor having a metal silicide layer. The procedure is comprised of multiple stages. When the spool rotates relative to the locking base in the webbing withdrawal direction, the torsion bar and the torsion pipe are both twisted and deformed, so that impact energy is absorbed. The assembly also includes a pair of fixation mechanisms for securing the first and second ends of the spring member to the pair of pedicle screws. The elements may be discarding using the priorities.