Features: Transform your 18V 21V power tool with DIY Wiring Converters, to seamlessly integrate with wide ranges of 18V 21V batteries, including BL1860B and BL1850, providing power output or charging input functionality. from plastic, this battery holder feature with 4cm contact spacing, ensuring compatibility with 18V 21V lithium batteries for use. for DIY enthusiasts and professional tradespeople who seek to enhances the versatility of their 18V 21V tool collection by converting existing setups into more efficient systems. for workshops, garages, or on site projects where quick power access and efficient battery management, allowing users to their tool performances. This battery adapter offer a practical solution for those lookings to customize their power tool, making it essential accessory in any toolkit. Specifications: Materials: Plastic Size:11x7x3cm/4.33x2.76x1.18inch Package Includes: 1PC Battery Mount Connectors note: Please allow 0-1cm error due to manual measurement. make sure you not mind before bid. Due to the differences between different monitors, the picture may not reflect the actual of the item.