It uses a type-c interface, which is rechargeable and the pins can be replaced. After many hardware updates and parameter modifications, the current generation is very easy to use. As long as the indicator light flashes, it must be good. Since there are many kinds of peripheral circuits of optocouplers, if it is always on or off, remove the light If you test the coupling again, you can 100% judge whether it is good or bad. Before testing, the motherboard must be powered off and then discharged. Testing cannot be carried out while the power is on. The pin marked on the device corresponds to pin 1 of the optocoupler, and it from top to bottom. If the optocoupler pins are rusty or have glue, you can clean them a little in advance. Different batches may have different appearance, which does not affect use. Colour: Green Material: PCB+electronic components Package Contents: 5 x Optocoupler 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.