It uses Type-C interface, built-in battery, rechargeable, and replaceable probes. Three test methods: plug-in test pad, patch test pad, probe on/offline test. Probe on/offline test: Online test after the motherboard capacitor is discharged, it is strictly forbidden to test when the motherboard is powered off, and the optocoupler can also be disassembled and tested offline. Patch test pad: The maximum testable patch optocoupler is 7.6 (excluding pins)x3.6mm, and the minimum testable patch optocoupler is 3.8 (excluding pins)x2mm. Applicable to 4-pin optocouplers, other types of optocouplers are not applicable for the time being. Note:This product is only for professional electronic maintenance personnel. People who do not have professional electronic knowledge should not buy and use it! After many hardware updates and parameter modifications, the current generation is very easy to use. As long as the indicator light flashes, the optocoupler must be good. Since there are many types of peripheral circuits of optocouplers, if it is always on or not, remove the optocoupler and test it again to judge whether it is good or bad. Before testing, the motherboard should be powered off and then discharged. Do not test with power on. The marked pins of the device correspond to pin 1 of the optocoupler, press from top to bottom. If the optocoupler pins are rusted or have glue, you can clean them slightly in advance. Please bring your own power cord. Colour:Green Material:PCB+electronic components Package Contents: 2 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.