These are custom made inserts to fit any habitat or enclosure.
All I need are the inside dimensions and the size of the opening to the enclosure. With these measurements I can create an insert that will fit perfectly into the unit and utilize as much of the interior space as possible.
These inserts are made with an epoxy, so there are no mould or fungus issues. You can purchase one of these inserts and it will last as long as you keep the habitat.