Zoo Med Hermit Crab Soil BrickZoo Med Hermit Crab Soil Brick is a compressed coconut fiber substrate for hermit crab enclosures. It increases humidity and encourages burrowing. It also absorbs odor and breaks down waste material. Compressed coconut fiber substrate can be safely composted or recycled. Each brick is 650 g and expands to make 7 8 liters of substrate Increases humidity and encourages natural burrowing Absorbs and breaks down odor Made from an eco friendly resources