Leemyungsu Design Lab was established for developing innovative wearable product which combined with people oriented design and technology. SEIL-bag is a wearable item collaborated with technology and fashion, which provides bike riders to display the direction, stop, and other emotional signals. The design philosophy of SEIL-bag is SEIL(Safe Enjoy Interactive Light) communication. Wearing SEIL-bag, they would like to provide safety based emotional joy and fun to their customer’s outdoor life. SEIL is composed of 3 main parts – an LED display, a back pack (or other type of wearable items specially designed to be compatible with the LED display), and a controller. The LED display is located in the outer pocket of backpack and the controller is equipped on the handle bar of the bicycle or on the wrist. The controller communicates with the display by Bluetooth. While riding a bicycle (or skateboard, snowboard, …), the rider can stay safe and enjoy by showing direction signals, stop signal, night signal, and other emotional signals using the ergonomically designed controller. We also provide apps, which can express the rider’s own designed signals, to enhance the variation of the expression on the display board.