Specifically designed to be used in wet and humid environments such as poison dart frog terrariums. Each bag contains finely ground tree fern fiber, milled long fiber sphagnum moss, milled sphagnum peat moss, fine charcoal, fine fir bark, leaf litter, and Bio Revitilzer. Each bag is made individually guaranteeing the correct ratios. This precise combination allows for excellent moisture retention and superb drainage leading to a substrate that will not easily become compacted or anaerobic in terrarium conditions.