Eyepiece

An eyepiece was a device containing a lense that could be attached to a Kanohi, allowing the wearer of the mask to zoom in or out. On Metru Nui, eyepieces were crafted by maskmakers. They were popular among Ko-Matoran seers. It is known that before he became a Toa Metru, Vakama made Nuju one for his Matatu.

Masks with eyepieces

 * Akaku (Great version)
 * Matatu (Great version)
 * Akaku Nuva

Trivia

 * Eyepieces are still active even after undergoing a Hordika transformation, as shown when Nuju used his to find Norik in Web of Shadows.
 * Matoran can also use eyepieces, as both Matoro and Nuju have at many points.