Experience precision and reliability with the Pyrex 5640-250 Volumetric Flask, a must-have for professionals in medical, biological, and physical laboratories. Crafted from high-quality borosilicate glass, this 250 mL flask is designed to deliver accurate measurements and withstand the rigors of daily laboratory use. Equipped with a stopper for airtight storage and sample protection, the flask is manufactured in the United States and meets the stringent standards of a Class A verified laboratory instrument. The model 5640-250 is a testament to Pyrex's commitment to durability and scientific accuracy.