Serum vials are ideal for long and short term sample storage, lyophilization and for vaccine injectable drug containers. The blowback feature in the neck and specially designed bottom radius, for added strength, are important for lyophilization applications. Clear vials are manufactured from low extractable borosilicate glass that conforms to ASTM Type I, Class A and USP Type I requirements. Vials are packaged in shrink-wrapped modules to greatly reduce particulate contamination. Note: Select aluminum seal and stopper size by using the mouth OD dimension of the vial.