ControlTech Di2 Battery Holder

A sleek, featherlight solution for Di2 battery storage, Controltech's battery holder securely mounts your power source inside the seatpost. The ribbed rubber construction gently grips the battery while absorbing vibration, protecting your investment from damage. Custom-designed for both 27.2mm and 30.9/31.6mm seatposts, installation takes seconds. Simply slide the flexible holder into place, insert your battery and go. At just 6 grams, you'll forget it's even there. For over 20 years, Controltech has engineered components that blend performance, protection and stealthy aesthetics for an unrivaled cycling experience.