21. O-ring is located in the assembly that joins the 15-story steel outer case of the booster to its nozzle. 22. When the plug and outer casing are assembled, the pins are pushed down into the plug by the springs. 23. The vessel is considered to be vulnerable as its hull has no outer casing to provide extra protection against leakage. 24. In this type of lock, an outer casing has a cylindrical hole in which the " plug " is housed. 25. The vessel is considered to be vulnerable because its hull has no outer casing to provide extra protection against leakage. 26. Pacific Bell spokesman John Britton said the outer casings are made with Kevlar, the same material used in bullet-proof vests. 27. Tubing might be used as the outer casing of such centrifuges, said the official, who spoke on condition of anonymity. 28. Upon reaching the ocean surface, the outer casing and parachute break away from the SLDMB, and the spring-loaded antenna deploys. 29. The massive outer casing is connected to this through similar leaf spring packs, but is free to move torsionally, with damping. 30. Gun barrels from retired M110s were initially used as the outer casing in the manufacture of the GBU-28 bunker buster bomb. 