I bought these because the batteries on x4n are quickly empty - although it only needs 5V 1 watt. This thing is very long and I only needed a 1 foot cord, as far as I can tell you can't find it. I cut it and put 2 butt connectors and jazzed it up with my short cable. Connected it to my Anker battery in my setup with a USB port. I then removed the batteries from the h4n to see if they were actually powering the unit. Guess it works amazing and it can last all day on my Anker battery. Get it, it must be.