SKS offers natural polypropylene plastic vials, including hinge top lids, with an added level of security with a tamper evident seal. The hinge top lids and snapped onto the plastic vials, and the tab locks into place. The tamper evident ring on the plastic vial will break, confirming your products have not been touched since filling. These plastic vials include a molded E.P.A fill line at the 100 ml mark for applications that require accurate measuring.