Tears of the Kingdom
"A Zonai device that can bring some light to dark places. It shines in one direction, and its light doesn't reach too far, but it can come in handy on dark roads or in caves."
They can be found in Zonai Capsules from Device Dispensers or Treasure Chests; or lying around in the overworld. If removed from a capsule, they cannot be returned to it, although they can be fused to weapons or shields.