Made of Type 1 clear borosilicate glass, these screw thread vials are designed with a continuous thread (CT) 20-400 finish, permitting a positive seal, ideal for a variety of uses including laboratory or manufacturer's use. These vials are packaged in cardboard boxes. You may also purchase polypropylene, foam lined, or closed top caps to accompany the vials. Contact us with any questions or if you would like a quantity price quote. Available while supplies last! All sales final.