Burette Straight Bore with Glass Key, Class 'A', with Batch Certificate

A burette is a graduated glass tube with a tap at one end for delivering known volumes of a liquid, especially in titrations. It is a long, graduated glass tube with a stopcock at its lower end. The flow of liquid from the tube to the burette tip is controlled by the stopcock valve.

A Class A burette is a type of laboratory glassware used for precise liquid dispensing, particularly in titrations, and is known for its high accuracy and reliability. It's a graduated glass tube with a stopcock at the bottom, enabling controlled delivery of a liquid. Class A indicates a specific level of accuracy, as defined by standards like DIN ISO 385.

Class A burettes are commonly made from borosilicate glass, which offers excellent chemical resistance and thermal stability.

Stopcocks act as valves, allowing precise control over the movement of fluids or gases. The plug is turned to align or misalign with the flow path, controlling the flow of the substance. Ground glass stopcocks require lubrication (usually with stopcock grease) to ensure a tight seal and smooth operation. Teflon stopcocks, on the other hand, generally don't require grease. 

Glass stopcocks are generally preferred over PTFE (Teflon) stopcocks when dealing with aggressive chemicals or high vacuum applications, as PTFE can be susceptible to damage or leaks in these conditions. However, PTFE stopcocks are often chosen for their ease of cleaning, ability to seal without grease, and suitability for sensitive chemistry where contamination from grease is a concern.

Specification:

• Graduated Glass Tube: Blue Graduations
• Stopcock: Glass
• Materials: Borosilicate glass
• Class: A Compliance with DIN ISO 385 and USP standard – IS 1997:2008