As-Sa'ib reported on the authority of a man whom he named: The Messenger of Allah ﷺ put on two coats of mail during the battle of Uhud as a double protection. (The narrator is doubtful about the word zahara or labisa.) (Using translation from Abū Dāʾūd 2590)
أَنَّ رَسُولَ اللهِ ﷺ ظَاهَرَ يَوْمَ أُحُدٍ بَيْنَ دِرْعَيْنِ