A novel headphone system includes a first speaker assembly, a second speaker assembly, and an interactive visual display system. The mechanism is placed between a processing element and a memory system such that write data is buffered and information based upon reads and writes is recorded. A user can obtain a replacement telescoping handle, release and remove a broken telescoping handle using the release and retaining mechanism, and then install the replacement telescoping handle. An integrator circuit outputs an integrated voltage indicating an accumulative rate of change of the product.