The voltmeter has high precision and high reliability, you can use it safely. It can endure 1min withstand voltage test of a sine wave with a frequency of 50Hz and an AC voltage of 2kv for 1min. There are three colors for the scale.(White Background, Black Word, and Red Pointer) The embedded installation is easy to wire. It& 39;s suitable for the power equipment and measuring the electric current directly.   Item Name: DC Pointer Voltmeter Material: Plastic Storage Temperature: -40~70 Degree Celsius Accuracy Grade: ±2.5% Insulation Resistance: >20MΩ/DC500V Damping Time: Less Than 4s Working Environment: Temperature: -20~40 Degree Celsius, Relative Humidity: ≤85% Type: 20 (DC0-20V)   30 (DC0-30V)   50 (DC0-50V)   100 (DC0-100V)   200 (DC0-200V)   300 (DC0-300V)   450 (DC0-450V)   500 (DC0-500V) Features: High Precision, Pointer DC Type, Easy Operation Size: 6.3cm x 6cm x 5.5cm/2.48" x 2.36" x 2.17" (Approx.)   Notes: Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.   Package Includes: 1 x DC Pointer Voltmeter Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin