Features: The 4 channel Battery Capacity Tester with internal resistance measurement supports charging/discharge cycles and up to 9 automated cycling tests, making it an essential battery analyzers tool for professional diagnostics. Featuring compact 18650 battery holders for flat top cells, this internal resistance meter incorporates active cooling fans and overheat protections to ensures stable operations during extended testing. Designed for electronics engineers, battery manufacturers, and DIYer enthusiasts requiring precise analysis of rechargeable batteries. Ideal for laboratory bench testing, battery recycling facilities, and repair shops needing simultaneous multi cell capacity verification and four wire resistance measurement capabilities. Its channel isolated design prevents operational interferences while maintaining measurement accuracy through advanced double wire methodology, though not suitable for LiFePO4 battery charging applications. Specifications: Component:ABS Type:Battery Capacity Tester,2P to 21700 Battery Holder,Battery Capacity Tester + 2Pcs Battery Holder,2Pcs Battery Holder, Package Includes: 1Set Battery Capacity Tester or Battery Holder note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color of the item.