RFTools Matter Transmitter
The matter transmitter is placed on the ground and (when dialed to a valid destination) will teleport a player that is standing on it. There is a fixed energy cost which is consumed immediatelly when the player stands on it. Then during the duration of the teleport (witch varies depending on the traveled distance) power is also consumed. If there is not sufficient power during the first power usage then teleportation will simply not start. But if there is a power failure during transit then potentially very bad things can happen to the player.
If you give the matter transmitter a name (by using the GUI for the transmitter) then that name will be shown in the dialing device which makes it easier to recognize.