This works surprisingly well for the price and size. The listed weight is correct at 2.9 ounces, but the power rating is overly optimistic. I think this will pass for the advertised 5W panel and I was able to measure almost 4W delivered to my battery in ideal conditions. As other reviewers have said, the USB port is easy to disable if the panel gets hot, so be careful when disconnecting! I wanted to remap this panel for use with a different voltage regulator, so I unplugged the USB connector (which voids any warranty) and directly measured the panel's characteristics: Voc 6.6 VIsc .82 AVmpp 5.6V, 3 .9 W per day in direct sunlight, immediately after sun exposure. He was also very tolerant of not being pointed directly at the sun. So if you don't expect the full advertised performance and are careful with the USB port, you'll be satisfied with this product in my opinion.