1. Backlight control: Briefly press the key to turn the backlight on or off. 2. Reset energy: Long press the key for more than 3 seconds can reset the energy. 3. Current indication: The current has a direction indication, if there is "-", it means the current is in the reverse direction, otherwise it is the forward direction. 4. Energy indication: Energy has direction indication, if there is "-", it means energy is reverse direction, otherwise it is forward direction.The energy direction is judged according to the current direction, if the current is positive, the energy will increase, the maximum is 999kwh, the overflow will be maintained unless you reset it; if the current is reverse, the energy will decrease, the maximum is -999kwh, the overflow will be maintained unless you reset it 5. Working mode: Direct power supply: direct supply by test voltage, test range is: 8-300V; power supply: working voltage range is: DC5-12V, test range is: 0-300V 6. Data retention: Energy data and backlight status can be saved after power off. Colour:Black Material:plastic Package Contents: 1 x Voltage Detector(300A) 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.