Double-jacket design with upper and lower side ports, enabling smooth circulation of temperature-regulating media for precise control. Made of thickened glass material, featuring stable structure and reliable performance for repeated experimental operations. Transparent glass body allows direct observation of internal liquid and reaction processes, supporting clear visual monitoring. Smooth rim and flat base ensure steady placement on work surfaces, compatible with standard laboratory supporting setups. Designed for laboratory applications, suitable for various controlled-temperature testing and reaction operations.