1. Digital multimeter: This power meter can measure and display voltage, current, active power, energy frequency and power factor at the same time.Use a shunt transformer for easier installation. 2. Overload alarm function: When the preset value exceeds the preset value, the backlight and power supply flash at the same time, and an alarm be emitted.You can preset your own power limit 3. Automatic data storage function: When the power supply is suddenly lost, the last be automatically stored.No need to worry about data loss caused by sudden power outages. 4. One-click control: buttons can be used to control backlight, reset energy, and preset power alarm limits 5. LCD display: Large-screen LCD display, full line of sight 180, blue backlight can be manually turned on/off.PZEM-022 requires an external power supply to light up the screen Colour:Black Material:ABS Due to different batches, there may be differences in product appearance and printed text, which not affect use Package Contents: 2 * power monitoring meters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.