Gearshift

Transmission (トランスミッション) was the Meta Ability used by the Second User of One For All and later inherited by Izuku Midoriya.

Description
Transmission allows the user to change the speed at which things accelerate through space. The user may choose to enter different "gears" to increase the speed a given object has. These gears are First Gear, the base speed that is activated upon using Transmission, Second Gear, Third Gear, and Top Gear, the final and fastest speed.

According to the Second User of One For All, Transmission has evolved into an unusual power that cannot be wielded the usual way. It has also been designated as a last resort. The second user told Izuku that once he used this Quirk, he would only have five minutes before he was out of the fight.

Usage
Not much is known about the Transmission Quirk when used by the Second User, but he has implied that the Quirk has been greatly been enhanced by One For All.

Izuku first used the Quirk to make all of his Ultimate Moves faster to the point where he broke the sound barrier, inflicting heavy damage to "Tomura" as the sound was delayed before it can be heard. All For One through Tomura was able to recognize the significant increase in speed and power from their original encounter.

Trivia

 * Transmission is one of the oldest known Quirks in the series along with One For All, All For One, Life Force, Spearlike Bones, Fa Jin, and the unnamed Luminescence Quirk.
 * The name of one of the "gears" of Transmission might a reference to the British TV Show , due to the Meta Ability and the show both being themed after cars.