The variable cross-section fuse body made by pure copper/sliver piece(or siliver wire)is sealed in the fusion tube which is made by the high strength porcelain; There is full of the high-purity quartz sand processed after chemistry to take the extinguishing of arc medium in the tube. The two sides of the fuse use the spot welding to reliably connect with the end plate(or junction panel)and to form the knife shape contact insert type structure. The fuse may have fuse indicator or striker, when the fuse element fusing it can demonstrate fusing 9indicator) or transforms each kind of signal as well as automatic transfer circuit(striker).