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.
O-ring - Other seals. 1  For sealings, there are variations in cross-section design other than circular. 2  There are also rings with a square profile, commonly called square-cuts, lathe cuts, or Square rings. 3  Similar devices with a non-round cross-sections are called seals, packings or gaskets.