A sensor for use in determining a level of a medium or detecting an object includes a plurality of spaced-apart electrically conductive members disposed on a nonconductive support. The first group of diffraction grating portions 20 has a first group of diffraction steps and the second group of diffraction grating portions 21 has a second group of diffraction steps, which is lower in height than the first group of diffraction steps. The plurality of contacts extend in a stacking direction of the plurality of conductive layers and insulating layers. The control logic is capable of receiving a data signal at the communications port which includes a time value and a unique identification which corresponds to the towed vehicle in response to the electrical start signal. The present invention further comprises a fluorocarbon resin powder dispersibility improving agent consisting of the fluorine-containing organopolysiloxane, where e of the fluorine-containing organopolysiloxane is 0 and an organic resin composition containing such dispersing agent. The invention also relates to a method for injecting fluid, which uses the injection device according to the invention.