Simport Colored Closures Case T340NOSL by Simport Scientific GROUP: Lab Equipment & Accessories:Sample Collection & Processing:Miscellaneous Item Description: Caps, O-Ring & Loop, Natural, 1000/Case Packaging Desc: Cap With Oring Seal/Loopnatural 1000/Case Country of Origin: CA Harmonized Tariff Code: 3923.50 Product Description: Made of polypropylene. Molded with a deep internal lip that fits snugly against the interior wall of the tube thus preventing the contents from coming in contact with the seal or threads, thereby reducing the chances of sample contamination.