A power tong unit having a gear train in which one or more of the gears in the gear train have removable and replacement roller tooth elements, in lieu of conventional gear teeth. The image adjusting method includes following steps. In the master device, a picked-up sound signal input section inputs picked-up sound signals from a plurality of microphones. A remaining clearance may be identified between each of a plurality of manufactured sizes associated with the plurality of features and each of plurality of virtual conditions for the plurality of features to form a plurality of remaining clearances. The present invention also encompasses methods of making such compositions, and methods of using the compositions to treat conditions of the eye. A corporate internet can maintain reputation data for web services to act as an auditor, and a web service server can also execute trusted code to act as an auditor.