Features: Achieve highly accurate measurements for lithium batteries internal resistance with our 4 wire testing technology and 1kHz signals, ensuring reliably results for your 18650 and 21700 cells. This compact battery resistance meter features two 0.56" displays (red for voltages, blue for resistance) with automatic mΩ/Ω unit switching for effortless operations. Ideal for electronics professional and DIYer enthusiasts who require precise battery health diagnostics for their projects and maintenance tasks. Perfect for workshop use or on site testing, thanks to its portable design (48x29x22mm, 88g) and wide DC4-12V power compatibility. Quickly identify battery performances issues and ensures optimal power sources functionality with this essential lithium batteries internal resistance tester. Specifications: Component: plastic shell, metal Size:Approx.20.3x4.12x2.58cm/7.99x1.62x1.02inch Weight: 88g Working voltages: DC4~12V Measurement methods: 4-wire systems, 1kHz signals Voltages measurement ranging: DC0.00~45.0V Internal resistance testing ranging: 00.0mΩ~999mΩ, 1.00~2.00Ω Package Includes: 1pcs Battery Internal Resistance Meter note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you donot mind befores you order. 2.Due to the differences between different monitors, the picture may not reflect the actual color. Thanks for your understandings.