A redstone repeater is a block in Minecraft that can delay and lock redstone signals. It is an essential component in various redstone circuits that require signal emission to be repeated. Here are some key features of a redstone repeater:

• Delay: The distance between the two pins on the margins of every redstone repeater specifies the delay in redstone signal emissions. By default, a repeater is set to one redstone tick (1/10th of a second delay), but it can be set up to four redstone ticks (4/10 of a second or 0.4 seconds).

• Signal Repeating: A repeater can instantaneously relay any redstone signals it receives with only a 0.1-second delay. If a signal passes through more than 15 blocks at once, the redstone repeater can repeat it as well as amplify it to go further.

Redstone repeaters are used in various redstone circuits, including redstone clocks and machines with limitless loops. They are also used to extend the signal on redstone circuits that are longer than 15 blocks. By adding delays to a signal, you can create more complex redstone circuits that activate and deactivate with specific timing.