Lightning Release Chakra Mode

By wrapping their body in a layer of lightning chakra, that instead of being used offensively, is used to electrically stimulate the user's nervous system and speed up their neural synapses to react faster to danger and push their physical prowess to the absolute limit, allowing them to gain tremendous raw speed and monstrous power.

This armour, combined with taijutsu, allows A to utilise nintaijutsu. When using the armour at full power, it causes the tips of his hair spike up. and his reflexes are comparable to that of Konoha's Yellow Flash, making it difficult even for the Sharingan, to keep up with him. By combining this armour with the Body Flicker Technique, he can even dodge Sasuke's Amaterasu at a split second, as well as Jūgo's Cursed Seal Chakra Blast at point blank range. At maximum speed and power, only Naruto Uzumaki in his Nine-Tails Chakra Mode and Minato Namikaze's Flying Thunder God Technique are faster than he is.

The armour also increases the user's defences, drastically reducing, if not completely negating, damage from incoming attacks as even a direct Chidori from Sasuke was barely able to pierce A's chest. In addition, the armour seems to increase the users' strength, though this could be part of their own natural abilities.

Trivia

 * In lieu of tailed beast chakra, the Fourth Raikage uses this lightning armour to empower himself when performing the Lariat, producing the same effects due to his high-powered chakra.