Olmak

The Kanohi Olmak was the Mask of Dimensional Gates.

History
There were only two known Olmak in the Matoran Universe, both created by Artakha. One Olmak was Brutaka's, but was destroyed by Teridax and the other belonged to the Brotherhood of Makuta, but had been fused to Vezon's head.

Powers
It allowed the user to open a dimensional gate to transport a target to a different dimension or another location within this one. The portal would remain open until something passed through it, even if its creator was knocked unconscious. Your full body must be in the portal by the time it closes or the parts that didn't make it through will be cut off and left behind.

Example Usage
Tridax used an Olmak several times to enter alternate dimensions, where he caught alternate versions of Takanuva.

Great

 * A Toa in Jovan's Team (Formerly; now deceased)
 * Botar (Only twice)
 * Brutaka (Destroyed)
 * Toa Mangai Tuyet (Briefly, in an alternate dimension)
 * Makuta Tridax (Occasionally)
 * Vezon (Briefly, later fused to his face)