Earphone Jack

Earphone Jack is a Quirk used by Kyoka Jiro and her mother Mika Jiro.

Description
This Quirk manifests in Kyoka as jack-shaped earlobes that can be inserted into all sorts of objects and channel the sound of her heartbeats into them. They are sturdy enough to easily pierce materials like rock and concrete.

It also allows Kyoka to catch faint sounds, giving her the ability to hear across even extremely thick walls. She can also plug the jacks into the boots of her costume, which have speakers that allow her to shoot a concentrated blast of sound in a specific direction. This technique, however, can be countered with a louder, opposing source of sound.

It is a versatile Quirk that can stretch up to 6 meters and the sound radius is approximately 12 meters. Her jacks can also function as whips, being strong enough to shatter rock.

Named Techniques

 * Cancelling (相殺): This move allows Kyouka to block out other sounds.
 * Heartbeat Fuzz (ハートビートファズ): A special move, Kyouka plugs her jacks into the amplifiers on her forearms. Kyouka then slams the amplifiers onto the floor and channels a powerful heartbeat through them that shatters the ground.

Trivia

 * Horikoshi mentions that this Quirk is possibly the first one he came up with, way before he even started planning My Hero Academia.
 * This is the first Quirk, other than One For All, that is shown to be used by multiple people, those being Kyoka and her mother.