DEWALT 18V - 20V MAX* Adapter is designed to enable the use of 20V MAX* Lithium Ion batteries with most 18V DEWALT tools, providing greater flexibility and convenience for users who want to maximize their battery compatibility. This adapter requires a 20V MAX* DEWALT charger to function properly. Please note that it is not compatible with premium DEWALT batteries used in DC970 or DC759 tools and will not work with 20V/60V FLEXVOLT Batteries, ensuring you select the right battery for your tools. Model Number: DCA1820