Jungle Base is a substrate material to be spread on the bottom of aquarium tanks where water tends to be stagnant in paludarium. Pumice is used as the base for Jungle Base combined with soil microorganisms effective for the plant growth and charcoal powder which maintains breathability in the substrate and prevents plant root rot. Please use it with optional Jungle Soil.
 
for more info
https://dooa.jp/en/products/2019/12/jungle-base/