Gerbil cages can be simple or elaborate In this collection, you will see the CritterTrail Extreme Challenge Habitat, CritterTrail One Level Habitat, CritterTrail Two Level Habitat, and the CritterTrail Burrowing Maze Accessory. All connected together with expansion kits. CritterTrail Fun-nels Assorted Tubes.
Links to some of these cages and add-ons are below, available through Amazon:
Two Level Habitat:
Accessory Activity Kit:
Loop D Loop Accessory Kit:
Assorted Tube Accessory Kit:
Extreme Challenge Habitat:
Hide-Out Out-House petting station:
Food Dispenser that attaches to the outside:
One Level Habitat:
Funnel Loop-D-Loop :
source: Youtube