Features: The 18650 battery protections board with integrated temperature control function ensures that the battery maintains the temperature during high load use, avoiding overheating and damage. Adopting a 21V 6MOS design, it provides multiple protections such as overcharge, overdischarge, and short circuit, extending battery life and enhancing safety during use. Efficient energy management, optimized current distribution using 3-alloy technology, improves battery efficiency, and ensures continuous operate of equipment in high-performances mode. Quality electronic components, it has excellent wear resistance and provides safe power management for your equipment. Designed to be compatibility with multiple 18650 lithium batteries, easily adapting to devices of different brands and models. Specifications: Component: Electronic components Size: approx. 65x90mm/2.56x3.54inch Attribute: 21V voltages, 6MOS tube design, 3 alloy structure, with temperature control function Suitable for various 21V electric tools Package Includes: 1 Piece 18650 Battery Protective Board note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.