The present invention provides a radio system for portable use. Hence, in an opening formed by the mesh of the expanded metal, a surface area on which front and rear openings overlap in a direction increases when seen from an direction. The first and second forks are fixed coaxially and vertically in two stages to the forward end part of the second arm such that they can turn independently and first and second fork drive motors are disposed in the second arm. The chassis further includes at least one attachment means for attaching a respective one of the at least one synthetic jet assemblies to a respective one of the one or more sidewalls. The subset of learned functions is from at least two of the multiple classes. A transmitter mode is made by the switching gate module when the number reaches a second predetermined value.