"Kopaka stepped away from Pohatu and activated the power of his mask, enabling him to peer through tons of stones into the network of caves within Mount Ihu. It was the work of moments to find a cavern in which there was a lone KanohiHau Nuva, the Mask of Shielding."
The Akaku Nuva was the Kanohi Nuva Mask of X-Ray Vision, created when a destined KanohiAkaku was dipped in Energized Protodermis and transformed. The Akaku Nuva gave its user and those nearby the power to see through solid objects and illusions. Akaku Nuva were fitted with telescopic lens to give the user(s) enhanced viewing. For some reason, this mask's power could not pierce the mist in Karda Nui or the domes of the Matoran Universe. The only beings able to activate this mask's power were Toa Nuva.