XO XRYG-280-3 will provide constant access to power for your devices. It is equipped with 2 USB-A ports and features a foldable design, so it won't take up much space. It will be perfect for a camping trip or a picnic. What's more, it offers 21 watts of power, and its energy efficiency is 22%.

Power    21 W max.
Open circuit voltage    21.6 V
Short-circuit current    4.5 A
Operating voltage    5 V max.
Operating current    4.2 A max.
Energy efficiency    22%
Output ports    USB-A x2