1. The battery box is a little tight. I use Sanyo eneloop rechargeable batteries () and fit them so rock solid that you can hardly get out again. There is acute fingernail breakaway threat. Maybe it is also due to the dimensions of the battery? 2 mm more housing length and some additional suspension travel when the battery contacts would have been enough in my opinion. Now I wrap before placing a small piece of foil around the batteries, which I can pull it out, the better.
2. The cut-outs on the battery box through which the rubber headband is performed, could also be a bit bigger. By the principle of operation of setting the tape length at the back of the head is double-layered and therefore (for me at least) also led twice through the cutouts, which is super tight then. It was quite a fumbling to get it sorted with multiple readjustment until my size and position fit 100%.
However, both criticisms are minor, especially as the length adjustment normally be incurred only once. Either way, I'm excited by the lamp and would buy again at any time!