The Iron Helm of Gorlim (+8,+8) [5,+10]
Heavily cursed. -5 intelligence, wisdom. -25% to searching. Provides resistance to fear. Cannot be harmed by acid, electricity, fire, cold. Prevents paralysis. Grants the ability to see invisible things. Aggravates creatures nearby.
Min Level 20, Max Level 75, Generation chance 20, 7.5 lbs

(Angband 3.1.2v2)