A method for tuning a tunable filter includes inputting a control signal to the tunable filter and tuning the configuration of the tunable filter according to the control signal. The method comprising providing a notification icon within a web page having a hypertext link associated with the hyperlinked document, selecting the notification icon, and notifying the user of any changes to the hyperlinked document. The noise filtering also protects the power line network data signals from noise generated by the devices plugged into the feed-through adapter. A part of or entire sections except the backrest section of the seat back pad are composed of a material S having a density lower than the density of a material R. Due to the one-to-one correspondent of each bonding pad with an ESD unit, the present invention ensures ESD continuity through a continuous charge dissipation path no matter what kind of pin-to-pin ESD test the IC is undergoing or how many power sources the IC has.