Repeater

The Repeater functions the same as its vanilla counterpart, except it has a total of 9 delay settings, ranging from almost instantaneous to more than 12 seconds. The different delay settings are 1, 2, 3, 4, 8, 16, 32, 64, or 128 ticks. For comparison, the vanilla repeaters settings are 1, 2, 5, or 7 ticks.

The Repeater also acts as a diode, meaning that it keeps redstone current travelling in one direction.

Uses
Normally, redstone current lasts 15 blocks. After that, you must have a repeater. The repeater expands the current by 15 more blocks. This allows for infinitely long redstone circuits, assuming Repeaters are placed as needed. They are also used to create circuits where a delay is desired, such as for priming TNT.

The repeaters, as part of the RedPower mod, can also stick to walls and ceilings, making them compatible with Red Alloy Wire. They may also be within the same block as a Cover.

Tick Length
As ticks relating to redstone are equal to two normal ticks, the different settings are as follows: