Pyrex Boiling Flasks, 500 ml, uses Stopper No. 6 (not includ

Round bottom Short ring neck These PYREX® round bottom boiling flasks have short ring necks. These ring neck boiling flasks are precisely tooled for uniform stopper fit. The reinforced rim increases mechanical strength. These flasks are used in applications requiring rigid stoppering and as wash bottles in routine lab washing. They are manufactured from No. 7740 borosilicate glass. Wall thicknesses are carefully controlled to provide the proper balance between thermal expansion and mechanical strength for greater shock resistance. Their excellent chemical durability results in contamination-free results and long life under the toughest lab conditions. The normal working temperature for PYREX® boiling flasks is 230°C. Note: Stoppers are not included with these flasks. See each individual listing to see what No. stopper each flask can use.