The new GuoGuan YueXiao Dual-Adjustment kit is a full hardware set that allows for the installation of the dual-adjustment mechanism in the GuoGuan YueXiao. The kit includes 1 core, 1 nut adjustment wrench, 1 screw adjusting wrench, 7 elastic adjusting nuts, 7 dual-adjustment springs, 7 washers, 7 springs, and 6 center pieces.