The Nekteck 28W solar charger is a reliable and efficient option for charging your devices on-the-go. With its high-efficiency Maxeon solar cells, it can charge two devices simultaneously with a total output of 5V/4.0A Max. However, keep in mind that the actual output capacity of the USB ports may vary depending on sunlight conditions. Overall, the Nekteck 28W solar charger is a great investment for anyone who spends a lot of time outdoors and needs a reliable source of power for their devices.