Zonaite Shin Guards

Inside the spherical island near the Gikaku Shrine.

In the upper half of the island, there’s a giant switch that you can push by placing heavy objects there, like Zonai Devices.

This will cause the exterior of the island to rotate. If you’re inside, it’s a bit tricky, but you can use Ascend to escape.

When you’re outside, glide/fly towards the lower half of the island and enter via the rotating circular hole.