The CellMeter 8 is a battery testing instrument designed to detect the status of various rechargeable battery types. Supported battery types include:Li-Ion (Lithium-Ion)Li-Po (Lithium Polymer)Li-Fe (Lithium Iron Phosphate)Ni-Cd (Nickel-Cadmium)NiMH (Nickel-Metal Hydride) For lithium batteries (Li-Po, Li-Ion, Li-Fe), the CellMeter 8 supports 2S to 8S packs without requiring an external power supply. If you want to test a 1S lithium battery, you must connect a nickel battery (3S or higher) or a 5V UBEC to the NiCd/NiMH port to power the device. For nickel batteries (Ni-Cd or NiMH), the CellMeter 8 supports 4S to 8S packs without requiring external power. To test nickel batteries below 4S, you'll need to connect a 2S–8S lithium battery to the Lithium port to provide working power to the CellMeter 8. Specifications: Material: ABS Size: 9x5.8x2cm Color: Black Package Contents: 1x CellMeter8 Digital Battery Tester