Only for use with Ferret Stack models #58501, #58502, and #58503 Cannot be used as a stand-alone cage Includes 1 Platform, 2 Ramps, assembly hardware NOTE: If adding this to a 3-Story cage, the finished 4-Story cage should be anchored to a wall for safety Cage portion measures 31"L x 20"W x 20"H, Wire spacing is 7/8-inch