This is a special bath salt containing Aomori Hiba essential oil in salt that's made by pumping underground seawater that contains a lot of natural minerals from the Tsugaru Straits.
The Hiba is a slow-growing, long lived cypress tree that is native to northern Japan’s Aomori prefecture. It is one of the three largest tree species of the Japanese cypress family, alongside the Hinoki and Sugi. Hiba trees take up to 300 years to grow into a highly durable tree with a natural resistance to mildew growth. Hiba wood has been highly valued as a building material in traditional Japanese architecture.