Kaytee Crittertrail Lazy Lookout Accessory Kit Includes: 1 - Lazy look-out Accessory, 1 - J-Tube, 2 - 3.5" Tubes, 2 - Connector Rings Universally connectable Each tube has ventilation holes for your pet's safety Assembled size is 7" long, 7" wide, 17.5" high For hamsters, gerbils or mice