A heat dissipation structure includes a heat conduction support body disposed in a handheld electronic device. In a preferred embodiment the SiGe circuit device includes one or more silicon germanium heterojunction bipolar transistors or silicon germanium carbon heterojunction bipolar transistors that is electrically connected across the electrical leads of the GMR read head. The print assembly can be used at fast print speeds of 2. The transportable platform may include a hitching element and a pair of wheels for towing and transportation. A first outlet is coupled with the main conduit for dispensing the viscous substance. In accordance with commands transmitted from the central controller over the control channel, content signals may be sent from any of the IPLDs to any other of the IPLDs, or from the central controller to any of the IPLDs, or from any of the IPLDs to the central controller.