The Kanohi Iden was the Mask of Spirit. It allowed its user to release one's spirit from one's physical body for a limited time. While free, the spirit could move at high speed, pass through physical objects, and observe events in the physical world. The spirit was invisible to anyone not using a Kanohi Elda or Kanohi Rode. Likewise, the spirit could not interact with any physical object or communicate with anyone not using one of those two masks.
The Kanohi Iden was the Mask of Spirit. It allowed its wearer to release his astral form, which could pass through solid objects and fly at great speed, but was invisible to others.
Beings who possessed telepathy could still use it while in spirit form, since telepathy was a mental ability.