_f. Firers and assistants._ One man carries and fires each flame thrower. Well-armed assistants accompany firers to give close protection and to serve as emergency replacements. Whereas the M1A1 portable flame thrower may require the help of an assistant to open the pressure-tank valve, the M2-2 flame thrower pressure-tank valve is located within reach of the firer and is operated by him without assistance. Firers and assistants should be thoroughly trained in operation of the weapon. [Illustration: Fig 4. Tank group.] _g. Charging and filling._ In order to replace pressure tanks (cylinders) of earlier types of flame throwers, it is necessary to unscrew and screw threaded connections. Experience has shown that this frequently resulted in damage to threads, leakage, loss of pressure, and loss of range. It is also necessary to use tools to replace each pressure tank (cylinder). The design of the M2-2 flame thrower eliminates these difficulties. The tank group (Fig 4) may be charged and filled as a unit with or without gun and hose. The quick-connecting tank coupling permits rapid interchanging of empty and full tank groups by the firers or assistants. This is done without tools, takes very little time, and cannot cause leakage, loss of pressure, and loss of range due to damaged threads. 5. DESCRIPTION AND FUNCTIONING. The flame thrower consists of two major groups: tank group and gun group. Detailed descriptions of assemblies and parts are included in Paragraphs 66 through 76. _a. Tank group._ (Figs 4 and 5) Carried upon the firer’s back, the tank group holds fuel and pressure. The tank group may be identified as tank, fuel, portable flame thrower, M2, assembly D81-1-482. It consists principally of: (1) _Two fuel tanks_, holding a total of 4 gallons of fuel, and joined by a tank connector to form a single fuel reservoir. (2) _Pressure tank_, charged with highly compressed air or nitrogen used to propel fuel from the fuel tanks through the gun to the target. The tank is large in capacity to assure ample pressure and uniformly long range throughout the firing. (3) _Pressure-tank valve_, which releases air or nitrogen through the pressure regulator to the fuel tanks. The valve can be opened by the firer without the assistance required in the case of the M1A1 flame thrower. (4) _Pressure regulator_, which automatically assures delivery of air or nitrogen to the fuel tanks at the proper pressure. The regulator is located in a position where it cannot easily be damaged. (5) _Carrier_, which supports the tank group on the firer’s back and shoulders and secures it to his body. It includes body and shoulder straps and quick-releasing fasteners. _b. Gun group._ (Fig 6) Carried, aimed, and operated by the hands of the firer, the gun group ignites the fuel and directs the flame into the target. It includes: