This small-volume lyophilization Vacule® ampule can be flame-sealed or stored with a stopper in place. It is made of Wheaton 33® low extractable borosilicate glass, (meets ASTM Type I Class A and USP Type I standards). Two ampule sealing methods can be used. The Tip Sealing Method: Holding the ampule body, insert the ampule stem into the sealing flame. Heat the stem 3-4 mm from the top of the ampule, until the melted glass fuses into a smooth dome. Sealing Funnel-Top Ampules: The funnel-top ampule allows not only easier filling but also easier sealing. The Pull Seal Method: Hold the funnel op in the fingers of one hand. The flame should be approximately one-third of the way from the Gold Band and your fingers. As the glass softens, continue to rotate the ampule while pulling the funnel top off the ampule. This will require very little force, allowing the glass to seal itself. As the funnel top separates from the ampule, sealing occurs. This method can be used for all Ampule configurations.