The present invention provides a silicon-containing surface modifier wherein the modifier contains one or more of a repeating unit shown by the following general formula and a partial structure shown by the following general formula. In an initial crawl, the crawler creates a first full index for the document store. A transmitter fixed to a tire includes a pressure sensor for detecting the air pressure of the tire and an MI sensor for detecting magnetic fields generated by the permanent magnets. An air spring is associated with each plunger for balancing the weight of each plunger and its respective arm.