An Erlenmeyer flask, also known as a conical flask (British English) or a titration flask, is a type of laboratory flask which features a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist Emil Erlenmeyer (1825–1909), who created it in 1860. The mouth of the Erlenmeyer flask may have a beaded lip that can be stopped or covered. Alternatively, the neck may be fitted with ground glass or other connector for use with more specialized stoppers or attachment to other apparatus. A Büchner flask is a common design modification used for filtration under vacuum.