Permatill horticultural pumice soil aerator and orchid medium - gallon
Permatill is made from expanded slate and designed to add aeration to clay or compact soils. The chunks are small and fairly even, with lots of little bubble holes through out. They can be added to orchid mixes, or you can plant your orchids directly in them to grow semi-hydroponically. They also make a great addition to soil mixes for succulents and other tropical plants.
These are rocks, so quite heavy.
One loose gallon.