The Dr. JB Switchable 48 oz Jar Only takes a step up from the 32 ounce Dr JB's Hummingbird Feeder system! Once your favorite backyard Hummingbirds arrive, instead of filling your feeder numerous times a day, simply switch out the bottle with the 48 ounce jar! Using the base from your Dr. JB Hummingbird Feeder, just change the jar to meet the needs of your thirsty Hummingbirds! With the same wide-mouth design as the original 16 ounce, this jar is easy to clean, easy to fill. Material: High-grade, heavy-duty plastic which is very resistant to breakage. These jars are unbreakable (stronger than glass) while offering easy clean wide opening.