CritterTrail Fun-nels 35 Tube CritterTrail Fun-nel Tubes attach directly to each other and to the inside and outside of your CritterTrail home. If you can imagine it, you can build it with CritterTrail Fun-nels! The tubes are available in four colors and in a variety of shapes and sizes so you can create a huge playground for your pet. Our 3.5" Tube is just the right size for adding straight away connections to your maze of fun and are sold two to a package. With CritterTrail Accessories, your imagination is your only limit. Click here | 
