The Twilight Clock is a utility item that lights the portals to the Twilight Dimensions.
The Twilight Clock lights the Twilight Dimension portals. Right-clicking inside the portals will light them, just like Flint and Steel lights Nether portals.
The Twilight Clock has an infinite durability, which makes up for its expensive crafting recipe. It should be stored safely in a Chest when not in use.