The small box fixture, also known as the small box fixture, is an important part of the upper structure of the large-scale pre cultured anode aluminum electrolytic cell. It is used for the fast tightening connection between the bus bar and the guide rod on the 400 Ka pre cultured electrolytic cell, and works under the conditions of high temperature, dust and strong magnetic field. Small box clamp and hook assembly are composed of internal and external clamp assembly, fork screw rod, pin shaft, hook and other components.