Dual Pro Lithium Battery Gauge - Single - Rectangle Vertical Display One Size. Each Lithium Battery Gauge includes a Current Transducer (CT). What does this mean for you? Accurate real-time state of charge reading. Typical gauges cannot precisely detect lithium battery levels as they charge/discharge. The CT allows the gauge to accurately track amp-hours in and amp-hours out. PROView Link is a mobile app that allows you to monitor and manage the condition of your batteries. From your smart device you can:View real-time data as charging is in processReview charging data history (up to 200 Cycles)Know if your equipment is fully charged or where it is in the processSee exactly when a charger was plugged Specifications for Dual Pro Lithium Battery Gauge - Single - Rectangle Vertical Display: Manufacturer: Dual Pro Color: Black Package Contents: Dual Pro Lithium Battery Gauge - Single - Rectangle Vertical Display Dual Pro BFGVLITH: Lithium Battery Gauge - Single - Rectangle Vertical Display One Size