Top quality borosilicate glass Highly durable 3.3 low expansion ASTM E-438 Type I Class A borosilicate glass is used for PUREGRIP™ bottles and flasks. Bottle sizes come in 100 mL, 250 mL, 500 mL, 1 L, 2 L, 3 L, 5 L, 10 L and 20 L quantities, with a choice of clear or amber glass.