What is described are derivatives of benzoylcyclohexanediones of the formula and their use as herbicides. The lower undercoat layer arranged under the magnetic layer has a preferable surface characteristic and an excellent electric conductivity, and the magnetic layer formed as a thin film has a preferable electromagnetic conversion characteristic. The mask can conform to the contours of a user’s face by inflating or deflating the mask. The important goal of this invention is to provide a simple method for identifying signals that are corrupted by multi-path effects, and can be excluded from position calculation in the GNSS receivers.