Features: Experience rapid charging with our Protections Board, featuring advanced technology that significantly cut down charging time for quick power restoration, ideal for efficient tool operate. Built with a robust 7MOS highly power protections board and PCB , it ensures balanced charging across battery cells, enhancing durability and heat resistance for reliability performances. Designed for professional users, enthusiasts, and industrial workers who frequently rely on power tools, offering convenience for 18650 21V devices. Perfectly suited for demanding scenarios like construction sites and outdoor projects, where extreme temperatures and conditions require dependable charging solution. Enjoy broad compatibility for 18650 21V battery models, coupled with over current and over voltages safeguards for ultimately safety in both home workshops and industrial settings. Specifications: Component: PCB Size: Approx.86x62mm/3.39x2.44inch for 18650 21V systems Features: Using advanced fast charging technology, with equalization function, integrated 7MOS highly power protections Supports fast charging and has multiple protections functions such as overcurrent, overvoltage, short circuit. Package Includes: 1pc protections Board note: Please allow 1-3cm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual item color.