Abstract: An assembly for mixing and metering a foaming agent with a pressurized fluid output of a fire extinguisher, the extinguisher including a body with a trigger for issuing the fluid through an outlet. The assembly includes a manifold adapted to being attached at an inlet end to the extinguisher outlet, the manifold having an outlet end which is adapted to engage with an inlet of a flexible hose. A canister contains a volume of a fire retardant (dry or foaming) agent and is engaged to an intermediate location of the manifold between the inlet and outlet. In this manner, the manifold mixes the foaming agent with the fluid output prior to delivery through the hose.