One aspect of the invention pertains to a semiconductor package suitable for use in high stress environments, such as ones involving high pressures, temperatures andor corrosive substances. The preferred force restoring mechanism is a wave washer. A connection box may be configured to house lines proceeding from a signal source and terminating in the connection box for connection to the fixture. The cushion extends between the lower end of the first trailing arm and the free, upper end of the second trailing arm and serves to transfer and equalize pressures between the first and second wheels. The present invention ensures the reliability of downlink communication between the base station and the relay station, and the transmission of this feedback information would not cause effect on user equipment.