This solar panel is great. Folded up it’s about the surface size of an iPad and 1-1.75 inches thick depending on whether you measure the little junction box sticking out or just the depth of the panels. It’s under 3 lbs which keeps it plenty portable but you will still notice it in your backpack. 3lbs is definitely light enough and even though you can find slightly smaller, lighter panels here’s why you probably shouldn’t:

It isn’t always sunny. Even if you only aim to get 20 watts to fast charge a mid-tier power bank it’s great to have the surface area to catch up to 40w in ideal conditions because as the term implies, you often won’t be in that setting. There are going to be some rainy days were it’s inconvenient to get anything at all which is just a fact of life with small solar panels. But with ~4ft and 40w of solar capability, this can easily keep you going on cloudy days too. As long as it isn’t a total wash out and you can see a bit of blue sky somewhere this 40w panel will still catch 8-10 watts through some pretty serious clouds. A nice day with a clear view of bright sun will get you 33-38w and you can plug along at full speed, but those days when thick clouds won’t stay out of your way you can still catch a decent charge just getting 20-30% of the max input. Plus once the sun comes out and you get some direct access to sunlight you’re off to the races.