BD40BD20 battery adapter converts Black & Decker 40V lithium batteries to 20V lithium battery format for use with Black & Decker 20V cordless power tools. Enables extended runtime and greater convenience for indoor and outdoor applications. Superior Compatibility: Compatible with Black & Decker 40V lithium batteries (BL4040, BL4025, BL4045, BL4045F, etc.). Works with Black & Decker 20V cordless drills, impact drivers, brushless tools, chain saws, lights, blowers, and other outdoor power tools. Safe & Reliable: Built-in voltage protection circuitry. Constructed from high-quality ABS plastic for durability and safety. Easy to Install: Designed for seamless compatibility with 20V tools. Simple to attach and remove; fits securely and performs reliably. Adapter Only – Not a Battery: This is a battery adapter only. It is not a battery and cannot be used for charging. Do not insert the adapter into any charger — always remove it before charging the battery. Color: Black Material: ABS Package Contents: 1 × Battery Adapter Note: Color appearance may vary slightly due to lighting and screen settings. Measurement tolerance: ±1–3 cm.