A device for attaching an accessory to a licence plate, includes a licence plate attachment portion adapted for attachment to the licence plate; and an accessory attachment portion adapted for attachment to the accessory. The communication system includes a first transceiver connected to a first wire in the group of wires and a second transceiver connected to a second wire in the group of wires. A suitable device for the catalytic conversion of exhaust gases in an exhaust system is also provided. Here, when a user inputs renewal permission of safety stock quantity of circulation item, the information processing device calculates safety stock quantity of circulation items in the shifted phase.