KIMAX® 1000mL Florence flasks have a low coefficient of expansion to resist thermal shock. They are constructed with sturdy walls to minimize mechanical breakage, and reinforced tooled tops for strength and a secure stopper fit. Designed from ASTM Specification E1403, Type I, Class 1, requirements. Accepts #8 rubber stoppers. 6/Case. Kimble® #: 25000-1000.