Hyuga is imported from Japan and very similar to pumice. It has great aeration, drainage, and good water retention qualities. Works well with Akadama for a bonsai soil mix. Hyuga is recommended for pines and junipers. How to use: Hyuga is primarily used as a base layer in the pot when repotting. The purpose of it is to prevent compaction of soil near the bottom of the bonsai pot which can lead to root rot. Use Akadama or other bonsai soil mix as the middle and top layer for ideal potting conditions for your tree. Made in Japan. Bag contains 18L. Particles are approximately 12.7mm.