As ampoule, the shape of entry determines the type of vial. Largely, vial is classified into Injection vial, Screw vial, and Blow back vial. Besides these three common type, there are also other kinds of vials, such as Snap on, Groove, and Grand Seal.
Among them, the most commonly used vial is "injection" type, whose entry is closed with rubber and then sealed with aluminum cap after filling it.
Screw vial is a screw cap bottle which has a screwy line on the exterior of the entry part and mostly used for containing refined medicine.
Blow back vial has a groove on its entry, which makes it easy to lessen the interior pressure of the vial when lyophilization. Blow back vial is mostly used for containing material that needs lyophilization.