National Scientific 8-425 Screw-Thread Vials National Scientific Septa Pack. The screw-thread design allows a wide range of applications such as storing and removing viscous liquids or powders. Due to the special manufacturing process these vials can withstand significant hammering forces. They are a practical and cost-effective size for storing and transferring viscous liquids or powders. The short length and wide-mouth design provides a tight seal without reducing the volume of the vial. This feature reduces the possibility of contamination from foreign particles in the event the vial is dropped. Keeping these vials clean also reduces the possibility of cross contamination. Thermo ScientificTM screw-thread vials are supplied with a wide variety of stoppers. Larger sizes have a ST stopper; however the smaller sizes have a flat base. Larger sizes have a large base possibly reducing the volume of the vial. National Scientific 8-425 Screw-Thread Vials National Scientific C4013-32 Septa Pack