A mounting apparatus for aiding in mounting a plurality of long expansion cards in electrical devices includes a rack, and a fixing member. In one embodiment, a conductive coil is embedded into the housing base, and a second coil is embedded into the filter element. A buoyancy block is disposed within the buoyancy chamber to move axially therein in a first direction responsive to rising of the fluid in the buoyancy chamber and a second direction responsive to lowering of the fluid in the buoyancy chamber.