Narrated Ibn Buraidah:
from his father: "An-Najashi gave the Prophet (ﷺ) two black plain Khuff. So he wore them, then he performed Wudu and wiped over them." (JA)
English reference (JA): Vol. 5, Book 41, Hadith 2820 (JA)
Arabic reference (JA): Book 43, Hadith 3052 (JA)