Safety pin, pressurized canister, hose, foam
[DOC] [TLE] How fire extinguisher is made - material, manufacture, history, used ... [PAR] The hand-held fire extinguisher is simply a pressure vessel from which is 
expelled a ... Generally, the agents applied are water, chemical foam, dry powder
, halon, ... stream through a hose or nozzle, pushed out by the stored pressure 
above it.