What are fire extinguishers called that have both the extinguishing material and expelling gas kept in a single container?

Stored pressure extinguishers are specifically designed so that the extinguishing agent and the expelling gas are contained within the same unit. This design allows for the immediate release of the extinguishing material when the operator activates the extinguisher. The pressure that expels the agent is maintained within the container, which simplifies the mechanism and makes it ready for use at a moment's notice.

This design is advantageous as it ensures that the extinguisher is always pressurized correctly and can be easily transported and stored without needing complex assembly or additional components. It's a common and effective model utilized in various environments, making it a standard choice for many fire safety applications.