The Flamethrower, Portable, No 2 (nicknamed Lifebuoy from the shape of its fuel tank), also known as the Ack Pack, was a British design of flamethrower for infantry use in the Second World War.

They were ready for service during Operation Overlord (the Allied invasion of Normandy).

In the middle of the "doughnut" was a spherical container holding nitrogen gas as a propellant, which was pressurized to 2,000 lbf/in2 (140 Bar).

A hose from the fuel tank passed to the nozzle assembly which had two pistol grips to hold and aim the spray.

In some versions the nozzle was fitted with a 10-chambered cylinder which contained the ignition cartridges.