A dielectric resonator for a negative refractivity medium, which is coupled to a plurality of substrates, comprises at least one crystal unit, at least one first crystal cube and at least one second crystal cube. A handle is detachably connected to an outer end of the bolt for pulling the bolt. During manufacture, one tool grasps the first peripheral surface of the first ring part and presses it into a pre-determinable shape and another tool supports the second peripheral surface of the second ring part. The present apparatus includes several input modules, a switch control output connected between the input module and a switch fabric, and a several output modules connected to the switch fabric. When the lever 2 is moved linearly from the rotation completive position, the lever fitting-type manual disconnector 1A is set in a fitting completive position where a fitting-state detective switch is turned on.