Specification Brand : TizZo BulletPoint1 : BulletPoint2 : BulletPoint3 : BulletPoint4 : BulletPoint5 : Color : Clear / 6" x 10" / 1000 Pack ExternallyAssignedProductIdentifier1 : 0779675550690 ExternallyAssignedProductIdentifier2 : 779675550690 IncludedComponents : Bag ItemName : Gas Sampling Bags with Single/Double Valve, 30mL~500mL, PTFE Aluminum Foil Air Bag, Gas Collection and Storage Bag, Keep Gas Away from Light - 5Pcs (5ml, Single Valve) ItemPackageDimensions_Height : 3 inches ItemPackageDimensions_Length : 3 inches ItemPackageDimensions_Width : 6 inches ItemPackageQuantity : 1 ItemShape : Square ItemTypeKeyword : science-lab-sample-bags Manufacturer : TizZo Material : aluminum, PTFE,PET,PP ModelNumber : 5ml~500ml NumberOfBoxes : 1 NumberOfItems : 5 PartNumber : TizZo-SamplingBag ProductDescription : Single Valve Bag It's a sampling bag with only one valve installed. Double Valve Bag It's a sampling bag with two identical valves installed on it. The inlet and outlet of the single valve sampling bag pass through one valve Differences One valve of the double valve sampling bag is inlet and the other is outlet. The advantages of the double valve bag are: several small capacity air bags can be connected in series to form a large gas sampling bag; and one in and one out is convenient for cleaning the gas sampling bag