Features: This product is fully-functional, you can display the battery voltage, battery power, you can also-plug directly into the phone or other equipment-charging. This product is suitable for all kinds of outdoor-power, mobile power, instrumentation-and other equipment additional battery power voltage display and additional USB to charge the phone and other functions. This product uses synchronous rectification step-down chip scheme, low heat, energy saving and environmental-protection. This product is-compact in structure, making full use of space and reducing-costs. Can be used as battery voltage meter, battery capacity tester and temperature indicator panel for car, marine, boats, etc. Specifications: Material:ABS Indicator Size:Approx.6.12x3.33x1.4cm/2.4x1.31x0.57inch Current: 50A 100A 300A 500A Package Includes: 1x Battery Capacity Indicator note: ①.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. ②.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks for your understandings.