<p>" CritterTrail Bubble-Plugs are used to close opened accessory holes on the sides of CritterTrail homes. Bubble Plugs can also be attached to a 10"" Fun-nels climbing Tube to close an opened accessory hole on the roof top of any CritterTrail home. Bubble Plugs are available in four colors and are sold two to a package."</p><ul><li>"2.25"" Diameter (2-Pack)"</li></ul>