Redstone Comparator

Redstone Comparators are items that will be added in a Future Update. They are a redstone-related item.

Uses
They are primarily used in redstone circuits to maintain, compare, subtract signal strength, or to measure certain block states, including the fullness of containers such as Chests, Brewing Stands, Furnaces, etc.

Trivia

 * They are often confused with Redstone Repeaters.