The helm was bulky and able to adjust to fit on a creature's head.
When worn, the wearer was able to identify the location and type of every devil within 1,000 feet (300 meters). The helm allowed the wearer to communicate with either a single devil, or multiple devils at once. This communication was done telepathically. The helm also allowed the wearer to cast dominate monster up to three times in a 24-hour period, but only on devils. If the wearer was within sight of a targeted devil while casting this spell, the devil would become aware of an attempt to charm them. If a non-devil wearer used this ability withing the Nine Hells, there was a chance it would attract the attention of a narzugon, who would then try to kill the wearer to recover the helm for its master.