Borosilicate glass have several groups, high borosilicate glass, middle borocilicate glass, low borosilicate glass.
As a newcomer, when we hear the borosilicate glass, we think that it is borosilicate glass3.3, which is also called high borosilicate glass. In fact, it is wrong.
This division fo the group, which based on the coeefficient of thermal expansion of the glass.