What battery does it use?
Wurkkos describes a 3.7-volt rechargeable battery that charges over USB-C and can be removed and replaced. Owners identify it as a standard 21700 lithium-ion cell, so you can carry a charged spare and swap it in when the first runs flat.
Is the brightness adjustment actually smooth to use?
The ramp itself is smooth and stepless, and you can set it exactly. The split in opinion is about the controls: one button and a rotary top handle everything, so it takes a little while to learn, and it might feel more natural if the knob controlled brightness instead of the button.
How long does the battery actually last?
Wurkkos gives up to 300 hours on the low brightness setting, and much less should be expected at full output. On low or mid brightness it can last several days, and battery life is one of the points they praise most. With a spare 21700 cell, runtime is limited only by how many charged batteries you carry.
Is it actually waterproof enough for real outdoor use?
Wurkkos rates it IP66, which means dust-tight and protected against strong jets of water, so rain is no problem. It is not rated for being held under water, so do not submerge it. Wurkkos also says it resists drops and impacts, and it feels sturdy.
Does the RGB feature actually work well, or is it a gimmick?
It is a real feature. Wurkkos lists nine rhythmic RGB modes, including a warning flash, and the colour and warm white settings work well for ambient light at camp, at outdoor events and during power cuts.
How compact is it really, and will it fit in a backpack?
Yes. At 4.17 inches tall and 3.84 ounces, it fits easily in a backpack or bag, and the small size does not hold back its brightness. It is a little heavier than it looks, because most of the weight is the battery.