Systems and methods of using a mobile communication device to present information related to a point of interest. The reactor core has a reaction surface and a combustion surface, each surface having a raised periphery defining opposing ends and opposing sides. The widthwise dimension of the design pattern is calculated on the basis of the edge points. The lower part of the device is the handle guide that keeps the shaft of the golf club in the proper position with the clubface square to the target. In other embodiments, additional differential pairs can be added to adjust for systematic offset voltages caused by process-induced variations in the structure of circuit devices or to induce a desired offset.