Sand-Filled: Used for Class B fires (flammable liquids) and electrical fires. The sand smothers the flames, cutting off their oxygen supply. It is also effective for absorbing small fuel or oil spills to prevent ignition.
Water-Filled: Used for Class A fires (solid combustibles like wood, paper, or cloth).
Absorbents: Sometimes filled with specialized materials like Flamezorb to soak up hazardous spills.