Opsak Odor Proof Bags100% watertight and airtight, the O. P. SAK (Odor Proof SAK) is also a 100% odor barrier bag. You can store food undetected to bears and other pests in your campsite by sealing them in the OPSAK. Also, because the OPSAK is FDA approved, you can use it in food preparation and storage. You can even pour boiling water into the OPSAK because of its extreme heat resistance. Each package contains two bags.