Maintain a hygienic terrarium with the Exo Terra BioDrain Draining Substrate for Reptiles, Amphibians & Bioactive Terrariums. This specially designed mesh is an essential component of the BioDrain Terrarium Draining System, keeping the decorative top-layer substrate separate from the draining substrate. This prevents contamination while allowing proper water drainage, making it ideal for creating water features and biological filtration systems. You can also use Exo Terra Terrarium Moss, Jungle Earth, or Plantation Soil as decorative substrates.