Aijiren 10mL & 20mL certified GC headspace vial is made of borosilicate glass. Clear and Amber color are available. The bottom of headspace vial has flat and round type. Headspade Vials with rounded bottoms are sturdier and more resistant to pressure than the flat bottom vial. As Headspace vials have to withstand high internal pressure, almost all 20ml crimp headspace vials have a wall thickness of 1.2mm. Thus it is guaranteed that the headspade vial will not burst. Contrary to a widely spread opinion, the seal and not the vial represents the weakest part of the whole sytem. Under pressure the septa will bulge against the Aluminum cap with such a force that the cap is torn apart. By testing, Aijiren varified that 10ml and 20ml crimp headspace vial can easily withstand 10 bars.