You can grow your dwarf hamster's (mouse's) habitat as it is compatible with all Habitrail items, though you must use the Habitrail Mini tubes.

The main area isn't as small as i anticipated and even the top compartment is of a reasonable size, I found it easy to put together including the tube clips. These Add-On items are escape-proof, ventilated and fun, and help enrich the life of your hamster as well as keeping a child owner entertained with the construction process. The Habitrail is meant to mimic the habitat of the animal in question, usually a warren, or series of tunnels. The Habitrail Ovo Suite is the hamster cage of the future, allowing you to create the coolest and most advanced hamster habitat ever!I stumbled across the video review below and thought I'd link to it as it seems to cover most of the main points - well done Happy Hamster, great review!

Good points, it is safe for dwarves, well ventilated, easy to clean, you can keep changing the setup to maintain your hamsters interest, it is very hard for them to chew as it is all curved, nice deep bases for dwarves for burrowing, the water bottle does not leak unlike a lot of people have said providing you follow the instructions properly and refill it daily completely to the top then turn it over three times to cr rate a vacuum, see u tube videos. Da dieses um die Ecke zu einem Schrank gehen sollte habe ich was mit Tunnelsystem gesucht und in Habitrail die Perfekte Lösung gefunden. It comes to bits for emptying all the mice stuff out and goes in the bath to be deep cleaned, dried and placed back together. Some mention that it's pretty easy to put together and seems well made, while others say that it is tricky to assemble and very time consuming, with poor instructions.Habitrail Retreat is a main habitat unit that serves as a safe and secure central living area for hamsters.

To ensure that these small pets can easily forage through their environment, the tubes in this habitat are narrower, thereby facilitating their exploring throughout their home. The bottom half of the home consists of a lightly-shaded plastic base that allows an unobstructed view of the interior, plus it prevents drafts. The elaborate world of OVO consists of a variety main habitats, add-ons, trails, and chewable mazes that are easy to assemble—in as little as 60 seconds in some cases—thanks to our exclusive Lock Connectors, that allow quick and easy connections. Das es dem natürlichen Bau (Höhlen u Tunnelsystem) des Hamsters entspricht merkt man an dem Verhalten!You will not be able to stop creating and creating spaces and habitats for the pet to enjoy a greater sense of freedom and autonomy.