Features: 1. Input and output voltage can be alternately displayed. 2. Boot status can be freely defined. 3. With a key switch function easy to control output. 4. High-power MOS tube reverse polarity protection circuit to improve efficiency and reliability. 5. Digital display color is green size is 0.98 inches. Instructions and precautions: IN +: Input cathode; IN-: Input negative; OUT +: Positive output; OUT-: Output negative; ON/0FF: Output control keys; S1: Mode Select key / memory key. Work Mode Description: Input voltage mode: the default boot mode input voltage display "** .*" LED indicator lights output closed. Output voltage mode: Press S1 once switched to the output voltage mode the display “** . * ”LED light is off turn off the display if the output 0FF. Alternating mode: S1 is pressed again Input / output voltage alternating turns 3S display data (press again to return to Input voltage display mode) Memory Mode : Press S1 button above 2S automatic memory module current work status as the default power-on state . When digital appears [ 0 ] represents the default boot display input voltage When digital appears [ 1 ] represents the default boot display the output voltage When digital appears [ 2 ] represents the default boot input / output voltage alternating Common voltage data test: ( closed digital test ) Boost efficiency buck efficiency 5.0V turn 12V/1A efficiency of 86.3%; 5V turn 3.3V/3A efficiency of 74.2% . 7.4V turn 12V/1A efficiency of 88.7%; 12V turn 5V/3A efficiency of 83.8% . 12V switch 18V/1A efficiency 88.3%; 24V switch 12V/2A efficiency of 86.4% . 18V switch 24V/1A efficiency 87.3%; 24V switch 18V/2A efficiency of 87.6% . Efficiency buck-boost mode 12V switch 12V/3A efficiency 87.4%; 5V turn 5V/2A efficiency of 81.4% .