CritterTrail fun-nels value packs are the perfect way to start expanding your CritterTrail home. The Bubble Wave tube design features a comfort grip that is safe for your pet's paws. Connector Rings snap on easily to ensure a safe and secure passageway. Easy to clean, tubes pull apart and snap back together for trouble-free cleaning. If you can imagine it, you can build it with CritterTrail fun-nels. The tubes are available in a variety of colors, shapes and sizes so you can create a huge playground for your pet.