Helm of Warning

This Headgear grants the intrinsic Warning, which allows the wearer to sense all monsters at a distance of 4 squares, regardless of light conditions, obstacles, or even blindness. If you cannot otherwise sense the monster, you will not be told its species, but you will get some hint of its level relative to your own. Note that like the messages from examining a monster, this hint takes no account of relative speed, special abilities, resistances, or other intrinsics. Thus, it's not necessarily a good guide to whether you can actually defeat the monster in question.