Kaytee Critter Trail Primary Starter HabitatKaytee Critter Trail Starter Habitat comes with everything you need for your first mouse, gerbil, or hamster. The habitat offers excellent visibility and ventilation while keeping your pets litter safely inside. Great starter home for small pets Includes everything needed to create a pets dream home Expandable design grows with your pet The expandable design allows the habitat to grow with your pet. Attach CritterTrail tubes and even entire habitats