This is a nest for ants with parts that can be snapped together to easily expand and customize your formicarium. There are two nests included, one for large ants, and one for small ants. Each has a water chamber to be filled with hydrated cotton, and a groove along the bottom to fit a reptile heating cable. Each nest is designed to fit a 3"x3" piece of glass on top. Also included is the very useful test tube adapter.