The Bell AH-1 Cobra (company designation: Model 209) is a two-blade, single engine attack helicopter manufactured by Bell Helicopter. It was developed using the engine, transmission and rotor system of the Bells UH-1 Iroquois. The AH-1 is also referred to as the Huey Cobra or Snake. The AH-1 was the backbone of the United States Armys attack helicopter fleet, but has been replaced by the AH-64 Apache in Army service. Upgraded versions continue to fly with the militaries of several other nations. The AH-1 twin engine versions remain in service with United States Marine Corps (USMC) as the services primary attack helicopter. Surplus AH-1 helicopters have been converted for fighting forest fires. The United States Forest Service refers to their program as the Firewatch Cobra. Garlick Helicopters also converts surplus AH-1s for forest firefighting under the name, FireSnake.