Fire extinguishers that use gas as the extinguishing agent are designed to suppress fires quickly and effectively without leaving a residue. These extinguishers typically use **Carbon Dioxide (CO2)** or **Nitrogen** gas to displace oxygen and lower the temperature of the fire.

1. **CO2 Fire Extinguishers**: Ideal for Class B (flammable liquids) and Class C (electrical) fires, CO2 extinguishers work by displacing oxygen in the fire area. They are commonly used in offices, server rooms, and industrial settings because they leave no residue, making them safe for sensitive equipment. However, CO2 can be hazardous in confined spaces, as it may lead to asphyxiation if not used properly.

2. **Nitrogen Fire Extinguishers**: Less common than CO2, nitrogen is used in specialized applications. It works similarly by reducing oxygen levels, and is often used in fire suppression systems for areas with valuable equipment or where a clean agent is essential.

Gas-based extinguishers are highly effective, particularly in environments where clean-up and equipment protection are priorities. Always ensure you’re selecting the right type for the specific fire risks you may encounter.