It is meticulously crafted from borosilicate glass 3.3, renowned for its exceptional resistance to heat and a wide range of chemicals. Compliant with DIN 12252 standards, this stopper ensures superior quality and reliability in laboratory settings. The lower closed end features a "drip-tip" design, facilitating the return of adhered liquids to the flask, thereby minimizing sample loss. Its hexagonal flat head design prevents rolling and allows the stopper to stand upright, reducing the risk of contamination on the ground surface.