Middle-set code

The utility model relates to the technical field of musical instrument accessories, and discloses a centrally-mounted standard which comprises a standard seat and a standard head, the standard head is detachably connected to the upper portion of the standard seat, the standard seat comprises a standard seat body and standard feet, the two standard feet are symmetrically arranged on the left side and the right side of the bottom of the standard seat body, and a containing groove is formed in the top of the standard seat body. The opening direction of the containing groove extends in the left-right direction of the code base body, an inserting hole extending downwards is formed in the bottom of the containing groove, an elastic piece matched with the inserting hole is arranged at the lower end of the wharf, the wharf is embedded in the containing groove, the elastic piece is inserted into the inserting hole, and the wharf can rotate leftwards and rightwards in the opening direction of the containing groove with