Fruits and vegetables naturally emit ethylene gas, which causes premature spoilage. GreenSaver Crisper Inserts mount with suction cups on crisper walls above produce to draw ethylene away with non-toxic enhanced carbon filters. Filters last 90 days. Pack includes 2 Crisper Insert and 2 filters. GreenSaver Crisper inserts are designed to keep your produce fresher for longer by slowing down the aging process Easy to use – just mount to your crisper drawer The enhanced carbon filter absorbs ethylene gas, which causes produce to rot Design promotes proper airflow for maximum absorption in crisper BPA-free Comes with one refillable enhanced carbon filter that lasts up to 90 days. Refills sold separately.