A proximity sensor is carried within a small diameter package and includes a magnet for providing a desirable magnetic field for operation of proximity sensing circuitry carried along a central axis to allow for a maximum sensor signal output with no change due to a relative rotation angle between the sensor and a target being monitored. A method of facilitating replacement of a supply of air freshener every time a supply of soap is replaced, including the steps of providing a supply of air freshener, providing a supply of soap and joining the supply of soap and the supply of air freshener. 25 time, are prepared and three sets of operational amplifier layout information are also prepared as a library in correspondence with the three kinds of shrink factors. Examples of vascular occlusions targeted by the system include, but are not limited to, atherosclerotic plaques, including fibrous caps, fatty buildup, coronary occlusions, arterial stenosis, restenosis, vein thrombi, arterial thrombi, cerebral thrombi, embolisms, hemorrhages, other blood clots, and very small vessels.