First, I must say is the second lamp I check, as the first one had the same problem and I returned it.
Both had the same problem: when you turns it on, weak light (red or white, is the same) brights. You continue turning the thumbwheel supposing that it will gradually increase brightness but that doesn´t happen. Only at the end of the wheel the light suddenly increases its brightness making it almost impossible to control (you have 10º or less of wheel turn to do that).
As the web announce it as "adjustable lamp" I think it must work like this: you turn the thumbwheel and the light smoothly increases from weak to full brightness as you turn the 300º of the wheel; only in this way you can get control and preserve your dark adaptation.
The construction is all plastic made, looks fragile and a small. To change the battery you must open the whole lamp, get the circuit (and its hard to extract) out and replace the battery. I think its bad designed as you expose the internal circuit every time you have to do that.