âSentry. A Sentry is a modified system monitor security program tasked with maintaining order on the Grid. Sentries wear standard black garb with red circuitry, and have black visored helmets with an open lower face below the visor. They possess identity discs, but most prefer to fight with their staffs.
Current Greenwich Mean Time (GMT) The Time Now is a reliable tool when traveling, calling or researching. The Time Now provides accurate (US network of cesium clocks) synchronized Greenwich Mean Time (GMT).
Both are time zones. GMT is Greenwich Mean Time, the official time at the Royal Observatory in Greenwich, England. For practical purposes it is pretty much the same thing, but it's more acceptable around the world because it doesn't sound quite so British.