Designed for extended runtime compared to our 2.0 Ah Battery Pack, the Blue Ion™ 4.0 Ah Battery Pack delivers optimal power and performance to your Kreg 20V Ionic Drive tools. A 4-LED charge indicator provides instant charge level feedback, so you always know when to recharge. Built-in smart charging technology and heat management protect against overcharging and overheating, ensuring long-term reliability. Backed by a 3-year limited warranty, this battery is built to keep your projects moving.