Used for an extension cable to connect solar panels to controller/battery for my ground installation. They worked great. It's a little tricky to plug into one of the outlets I have, but I can trim the plastic a bit to make it a little easier. The kit included a polarity switch and it helped me a lot so I could set my controller to red. too positive/black goes to negative (normal) instead of going back. I'm sure there was a small loss due to the 25ft line, but nothing to work on. I thought 25ft was MUCH more than I needed, but the first time I used it I almost ran out of cord! Great extension. Benefit from many advantages.