... , it will show battery voltage, for example, 3.7V will display “3.7U” .Lock protection: Press "-" and "+" button at the same ... "+" to choose the setting mode: "1.dR"-Display resistance, "2.dU"-Display Voltage,"3.dP"-Display wattage. After that press the big button ... show the resistance of the Cartomizer/atomizer, for example, 4.0ohm will display “4.0o”. if without Cartomizer/atomizer, it will show F1 ...