SEIL-bag is designed in order to illustrate traffic signals such as proceed signal, stop signal and emergency signal on the back pack. It is composed of detachable wireless controller and LED display which is built in the back pack. Bicycle riders could operate wireless controller to show left and right turn signal. Bluetooth-enabled device can connect between controller and back pack. Furthermore, user could make any texts and images they want through smartphone App and transmit data to LED display. Whenever App is running, user can make sure contents on the SEIL-bag in real time and wireless controller do not practice during walking.