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.
An O-ring is a solid-rubber seal shaped like a. doughnut or torus. When compressed between. mating surfaces, an O-ring blocks the passage of. liquids or gases. Parco O-rings are available in a. wide range of standard and non-standard sizes. that are suitable for nearly all sealing. applications. Two dimensions describe the size of an O-ring: its. inside diameter (ID) and its cross-sectional. diameter (CS) (see Figure 1).