Dear customer: Thank you for choosing my store for shopping. The following are the matters needing attention for shopping: A. Economic transportation: detailed tracking information will not be included. Most of the packages will cause delayed delivery within the expected delivery time, so you need to be patient B. Each product link: There will be different option variants. If you do nt know how to select the product you want, please contact me, I will be honored to solve this problem for you. C. When you receive the package, there is product damage / product problem / error product and shipping problem, please contact me in time, I will solve it for you! D. If you are a wholesaler / distributor, a large number of orders and quantities, to provide you with factory prices, and hope to be honored to reach a partner with you! GOOGZON store: I wish you a happy life! The factory has adjusted the internal interval of the PCB. If you have a back PCB board, please dont buy it. Working voltage of Meter itself:DC 4 - 30V(The maximum input voltage can not exceed 30V. Otherwise the meter will be burned) Working current of Meter itself:20mA Voltage Measuring range: DC 0 - 100V Current Measuring range: DC 0 - 10A Voltage resolution (V): 0.1V Current resolution (A): 0.01A Measure accuracy: 1% ( 1 digit) Display: 0.28" digital tube Refresh rate: about 300mS / times Dimensions:48mm*29mm*26mm Operation Temp: -10-+65