Specification Brand : TizZo BulletPoint1 : BulletPoint2 : BulletPoint3 : BulletPoint4 : BulletPoint5 : Color : Blue-10Packs ExternallyAssignedProductIdentifier1 : 0779675550881 ExternallyAssignedProductIdentifier2 : 779675550881 IncludedComponents : sticky swab gel ItemName : Gas Sampling Bags with Valve, 1L~30Liter PTFE Aluminum Foil Air Bag, Gas Collection and Storage Bag - 5Pcs (3L, Double Valves) ItemPackageDimensions_Height : 0.4 inches ItemPackageDimensions_Length : 4 inches ItemPackageDimensions_Width : 2.8 inches ItemPackageQuantity : 1 ItemShape : Square ItemTypeKeyword : science-lab-sample-bags Manufacturer : TizZo Material : aluminum,PTFE ModelNumber : 1L~30L NumberOfItems : 5 PartNumber : TizZo-GasBag1L-30L 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