At first use, this seemed like a great headlamp. Easy brightness adjustment, very bright on full, red light is great for buggy conditions, long battery life. But unfortunately it has one serious flaw. When you turn the light off, the little blue battery status / charging lights on the side stay on for 4-5 seconds. This "feature" is a scourge for nighttime wildlife watching. For example, say I'm trying to call up owls. If I have my headlamp on (say, I'm fiddling with recording equipment) and one calls nearby, I need my light off NOW, not 5 seconds from now. Those faint blue lights make you highly visible to an animal with night vision, perhaps even more so that the normal bright headlamp, which may reduce their night vision temporarily. This is a problem with most nocturnal mammals or birds: that five seconds of faint light (bright to them) tips them off exactly where you are, just when you are trying not to be seen. Now I have to stick a piece of duct tape over the charging lights on my expensive new headlamp—and take if off whenever I charge it. Not an issue for everyone, of course, but a big deal for me. And, I would suspect, any biologist who works at night. If that describes you, don't buy this headlamp.