Crafted for precision and reliability, the Pyrex 5640-250 is a 250 mL Class A Volumetric Flask, designed to meet the strictest measurement standards. It comes equipped with a stopper, ensuring contents are contained and secure. The flask's robust construction is matched by its ease of use, making it an essential tool for laboratory professionals. The flask's heritage is rooted in the trusted craftsmanship of the PYREX brand, known for its dedication to quality and durability. While the country of origin remains unspecified, the flask's model number 5640-250 and its verification as a Class A piece underscore its credibility and precision in scientific applications.