The Exo Terra Coco Husk Brick Tropical Terrarium Reptile Substrate is compressed coconut husk fiber bricks (coarse coco husk chunks) for tropical terrariums. When soaked, each brick expands into a loose, absorbent substrate that is excellent for retaining moisture and enhancing humidity. Coco husk chunks are larger than plantation soil fibers, allowing more aeration – great for bioactive setups with springtails or for animals like frogs, skinks, or arachnids that appreciate a humid microclimate. It’s completely natural and biodegradable all while providing a soft, natural bedding that encourages burrowing and helps control odor. Available in Multiple Sizes