A user at a client machine can customize components of a database search performed at a server. The two toroidal current instrument transformers are associated, respectively, one to elements for sensing the normal leakage current, and the other to elements for sensing the impulsive current, the latter comprising a circuit discriminating between \u201cswitching\u201d and \u201clightning\u201d signals, in which the basis for discrimination is a signal duration threshold, of about 35 \u03bcs. The receiving node receives the kinematic information and determines a future position and orientation of the sending node. The liquid introducing device introduces a liquid when the movable liquid tank is provided at an upper position. Promotional materials are provided to customer for revenue to third-party.