For hamsters, mice, and gerbils. 8 Oz Includes A Free Bottle Hanger For Hanging In Any Wire Cage, As Well As An Adjustable O-Ring Forinserting Into The Top Opening Of Crittertrail Homes, Other Modular Systems, And Keep-A-Critter Travel Homes. Fits In Holder To Hang In Aquariums. 8 OUNCES