Review on Dimmable USB Powered LED Bulb Night Light (7W) - Ideal for Home Reading, Camping, and Emergencies by Eric Speers

I chose this USB light because it has the highest power and the brightness can be regulated. As an emergency light, once your eyes adjust to the level of light, this light will provide adequate lighting for most normal tasks (other than reading fine print) in a large room. Don't expect it to illuminate large open areas. Brightness each time you press the up or down arrow. Holding down the arrow key changes the brightness continuously, but I've found that holding the key doesn't result in maximum brightness. After it reaches its maximum, it gets brighter with a few clicks. It worked when plugged into the USB ports of both my laptop's power adapters and the 120VAC to 5V USB adapter until the power button was pressed. But the little blue light on the switch shows it's connected. It is very light and therefore easy to take with you in your backpack. Please note that this is an area light, not a spotlight. So this isn't the light you need when looking at something with the light in front of your eyes. To do this, you need a flashlight or a searchlight. I wish it came with a storage bag to keep it dry and dust free, but it fits nicely in a zippered sandwich bag.