Buraydah (radiallahu anhu) says, "Najaashi sent two simple black coloured socks as a gift to Sayyidina Rasulullah sallallahu alaihe wasallam. He wore these and made mash over them after performing wudu". (JA)
English reference (JA): Book 9, Hadith 69 (JA)
Arabic reference (JA): Book 10, Hadith 73 (JA)