Seems to meet the intended purpose. quick delivery.

This device works very well and is 5 star--it tests for polarity and other wiring problems in a US standard wall socket. If you also have a GFCI (Ground Fault Interrupter), you can check its function using this device. You cannot track which breaker you are dealing with--the description is somewhat misleading on that.

And then you get to the instructions, which appear on two tiny pages. They are the most comical translations of instructions from Chinese to English you are likely to read. If you want a great laugh, buying this device just for its manual is worth it. Example: [If the polarity of the plug is correct] press the “Creeping Switch Test” button. in this case, if the earth resistance is canonically designed when the Earth Leakage Circuit Breaker works well, it will be tripping and power-off. If the Power Protection Systems works in failure, please contact careerman to make maintenance.

What they are testing is the GFCI. If it doesn’t work, call a professional to fix it.

This product is compact and functions well.