Features: This 4 Channel Battery Tester features reverse connection protections and testing capabilities for precise battery capacity assessment, ensuring safe and performances with support for 21700 cells. Equipped with an ABS air guide base and a large 40mm fan for efficient cooling, it allows simultaneous charging, discharging, or aging tests across all channels while displaying real time data on the LCD screen. Ideal for electronics enthusiasts, hobbyists, and professional who require accurate tools for evaluating battery performances and conducting battery detection tasks. Perfect for scenarios like battery capacity measurement, aging analysis, or charging/discharging tests in workshops, labs, or home settings, offering operate with adjustable discharge voltages. With high precisions capacity testing and Chinese/English interfaces, this battery tester delivers authentic data for battery detection and performances evaluations. Specifications: COmponent: Plastic Cooling methods: 40x40mm fan active cooling Reverse connection protections: support Host size: about. 147x102x33mm/5.79x4.02x11.3in Package Includes: 1pc Battery Capacity Tester note: Battery NOT Include. Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.