Converts for Black and Decker 40V lithium batteries to for Dewalt 20V max lithium battery, enhancing compatibility with various cordless power tools. Fully compatible with multiple Black and Decker 40V lithium battery models, including BL4040, BL4025, BL4045, and BL4045F. Built-in voltage protection chip ensures safe operation, while the high-quality ABS plastic construction provides durability. Easy to install and remove, designed specifically for 20V tools, ensuring a secure fit and reliable performance. Note that this is an adapter, not a battery; it cannot be used for charging power tool batteries and should be removed before charging. The BD40DW20 battery adapter allows you to maximize the use of your Black and Decker 40V lithium batteries with Dewalt 20V cordless power tools. This versatile adapter is perfect for drills, impact drivers, chain saws, and other outdoor tools, providing a seamless transition between battery systems. With its user-friendly design, you can easily install and remove the adapter, ensuring a hassle-free experience. The built-in voltage protection chip adds an extra layer of safety, making it a reliable choice for your power tool needs. Color: Black Material: ABS Package Contents: 1* Battery Adapter