Perlite (10ltrs) perfect for mushroom shotgun fruiting chambers.

It's perlite. 

From our suppliers website "Perlite is a naturally occurring volcanic rock which, when heated to high temperatures, produces lightweight micro-porous granules." which is pretty cool sounding.

Perlite is generally used in shotgun fruiting chambers to create a humid environment for your mushrooms to thrive in. 

It's safe to use, but can be a bit dusty, so maybe break out your old COVID era mask for this one or add water to suppress the dust.