N.A.T.O. The defensive military alliance formed in 1949 by ten european countries. WARSAW PACT A military alliance formed in 1955 by the Soviet Union Netherlands. Norway.
Tank Rings. Tank rings filled with gravel lift the tank above the surrounding grade. This keeps the tank out of standing water and increases the life of the tank bottom.
The O-rings in question are the large ones that are responsible for providing the seal between the alternating steel and aluminum sections of the engine. There are two sets of O-rings at each section joint--an inner one and an outer one. These O-rings function to keep coolant flowing through the passages from section to section. The outer O-ring keeps coolant from leaking to the outside of the engine.