Features: Supports four-channel capacity and internal resistance measurement. Support separate charging and discharging, and support up to 9 charging and discharging cycles in automatic mode-. Each channel is independent of each- other, set separately, operates independently, and does not interfere with each other-. 18650 battery holder uses compact- battery holder, suitable for flat-head battery measurement. Active cooling of fan supports overheating protection, Using -DC two-wire method- to measure internal resistance. Specifications: Material: plastic Package Includes: 1xBattery Internal Resistance Tester note: Please allow 1-3cm error due to manual measurement. please make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.