USB positive and negative can be separately drawn out for a range of applications The adjustment knob of the constant current potentiometer rotates clockwise to increase the current and counterclockwise to decrease the current Fan start and stop reserved port By default, the fan starts and stops automatically with temperature changes. When the middle pad is shorted to the 3.ON pad, it is normally open, and when it is shorted to the OFF pad, it is closed. Voltage: DC3,7-13V Adjustable current: 0,15-3,00A Power: 15W (continuous work) Fan working temperature: 40C Fan: Ball bearing fan High precision Frequency: standard Colour:green Material:plastic Package Contents: 1 x Electronic load resistance tester 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.