Suva were shrines found in the villages of Mata Nui, the Great Temple of Metru Nui, and various other places. They were commonly dedicated to individual Toa or groups of Toa. They were used as storage space for Kanohi masks. Toa were able to teleport their masks directly from suva to their faces.
The suva [in Ta-Koro] was a small, dome-like shrine in the center of the village.
The Toa did not carry all of their masks with them; to switch masks, they summoned them from their suva. If a Toa lost his mask, he lost access to all of his other masks. He needed to be wearing a mask to summon another from a suva.
When the Toa Nuva migrated from Mata Nui to Metru Nui, their suva stayed behind on Mata Nui, and they needed to have new suva created on Metru Nui if they wanted to use them to store masks again.