Round-bottom culture tubes are laboratory glassware used to grow and maintain cell cultures, bacteria, and other microorganisms. They are cylindrical in shape, with a round bottom that provides a large surface area for growth and allows for easy mixing of the contents. The tubes are typically made of durable, chemically-resistant glass, and have a screw cap for a secure and airtight seal.

The screw cap helps prevent leaks and evaporation, and also allows for easy dispensing of the contents. Round-bottom culture tubes are commonly used in microbiology, biotechnology, and other life sciences. They come in various sizes and capacities and can be used for a wide range of applications, such as culturing cells, bacteria, or other microorganisms, and for storing or transporting media and other samples.