The stem can be pull sealed or tip sealed to seal the ampule. The pre-scored feature saves time by eliminating filing. The clear glass ampules are made of Wheaton 33 expansion low extractable borosilicate glass that conforms to USP Type I and also ASTM Type I, Class A requirements. The amber ampules are manufactured from Wheaton 320 amber borosilicate glass that conforms to USP Type I requirements and protects light-sensitive samples.