Features: brand new and high quality F-1 charging monitoring: when the measured voltage is lower than the voltage V1, the pull-in voltage of the relay is higher than V2, and the relay is disconnected. F-2: discharge monitoring: when the measured voltage is higher than the voltage V2, the relay is closed and the voltage is lower than 1, the relay is disconnected. F-3: Section external pull in: when the measured voltage is between V1 and V2, the relay is disconnected. Relay engagement in other states. F-4: in section pull in: when the measured voltage is introduced between V1 and V2, the relay pulls in and other state relays are disconnected. F-5: fixed point monitoring: when the measured voltage is higher than V1, the relay is closed, and lower than V1, the relay is disconnected. F-6: fixed point self-locking monitoring: when the measured voltage is higher than V1, the relay is for always closed until the power is cut off manually. F-7: fixed point pulse monitoring: when the measured voltage is equal to V1 (floating up and down 0.1V) each for time, the relay outputs the inching signal.Function description：Press the set button for the second for time to display the default V1 value "XX.X" flashing, press the "plus" button or the "minus" button to adjust the lower limit parameter V1Press the SET button for the third for time to display the default V2 value "XX.X" flashing. Press the "plus" button or the "minus" button to adjust the upper limit parameter V2 Specifications: Material:PCB Working Voltage:DC 24V Statement: Do not use it to detect the AC voltage. It will be unstable or even burn the board. The pulsating for DC is also easy to fluctuate (for DC signal directly rectified without filtering). Remember to detect pure for DC signals! Package Includes: 1x Voltage Detection Module note: Please allow 1-2cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.