This product is a charging cable designed exclusively for the Di2 series electronic shifting system. It provides charging functionality only and does not support data transmission. The charger features an automatic full-power-off function to prevent overcharging and protect the battery. It also includes built-in safety protection to prevent damage to the system during charging. If the battery is fully depleted, it must first be activated using the original Shimano battery before normal charging and operation can resume. LED indicators: - Solid green light: Fully charged or cable inserted incorrectly (reversed). - Solid green + blinking red, or solid red + blinking green: Charging in progress. If the electronic shifting system does not respond after charging, press and hold any shifting button for 2 seconds until the indicator light activates; shifting will then function normally. Color: Black Material: Plastic Package Includes: 1 x Road Bike Battery Charger