Glass Erlenmeyer Flask Set - 3 Sizes - 50, 150 and 250ml, Karter Scientific 214U2 Contains 1 each 50, 150 and 250ml Flask High quality inert 3.3 borosilicate glass Heavy Duty Reusable ASTM Specification E960, Type I requirements ID/OD: 50ml: 24.5/30.5mm, 150ml: 32/37mm, 250ml: 32/37.5mm.