A pear-shaped flask with a joint is laboratory glassware used for various chemical reactions. The flask has a unique, pear-shaped design that provides a wider surface area for reaction and heating compared to a traditional round flask. The joint is a standardized connection between the flask and other apparatus, allowing for easy and secure attachment of a variety of accessories, such as a condenser or thermometer.

The joint allows for a sealed connection, which helps prevent leaks and spills during experiments. Pear-shaped flasks are commonly used in chemistry and chemical engineering and can be made of heat-resistant glass for heating and cooling applications.

They come in various sizes and capacities and can be used for a wide range of chemical reactions, such as distillation, reflux, and boiling.