I have made jumper cables before using any other cable and they have always worked. That sucks. I tried to make a 25 foot cable and it didn't work. Cut off the ends and try again. Not good. Tried a third time, still an error. I have a tester but there isn't much. You get what you pay for and it's a shame I didn't try it when I first bought it. I would return it, but I just went through the window for it. I think I could use it to hang clothes.