This device is used to measure and display parameters such as voltage, current, power, true capacity,battery temperature, low capacity alarm, low voltage alarm, Current voltage curve, Electricitystatistics,as well as remaining discharge time and remaining charging time of the battery pack. Itaccurately displays working states of the battery pack at any time This instrument is suitable for electric vehicles, RVs, cars, emergency power supplies, energystorage power supplies, measuring equipment, medical equipment, various instruments and otherproducts that use battery equipment. Suitable for all types of battery packs, including lithium batteries, lithium iron phosphate, lead-acidbatteries, nickel hydrogen batteries, etc., with operating voltages ranging DC 0~420V. Less than 10V, DC5V power supply is required for power supply! Built in WiFi module: Remote Control:Connect the CW24 meter Wi-Fi to 2.4GHz Wi-Fi, then you can monitor or adjust on your phone through the app at any time anywhere. feature: Two ways to test battery percentage You can choose one of the appropriate ways to test your battery! 1.C+D-Mode:Capacity Percentage test Mode,Charging(C+)Capacity Add and Discharging(D-)Capacity Rednce. 2.C+D+ Mode Cumulatiye Capacity Calculation Mode,Charging(C+)Capacity Add and Discharging(D-)Capacity Add not reduce Two valnes are cumulative! Voltage measurement range:DC0~420V Specification: 200A Color: Black Material: Plastic+Metal Package Contents: 1 * Coulomb Meter 1 * Shunter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.