Each piece is hand made and hand painted with animal safe material. It will not wear down over time! These inserts include a pre-cut area for a submersible pump that can create a natural waterfall and pond area! (see diagram). Each piece is uniquely designed and cut, including the caverns and craters! If you are using the insert with running water, the basic exo terra submersible pump that we sell ($9.95) will be ideal, and the foam will act as a biological filter for the water! Over time, healthy bacteria will build up over time creating a biological, self-sustaining environment! This is ideal for all amphibians, tropical lizards, snakes and more! Plants, moss and pump are sold separately. This 20 Gallon Tall Model has an area at the bottom that is ideal for tropical fish, aquatic frogs and more to swim in, and can be viewed from the front of the terrarium!