"I saw the Prophet (ﷺ) wiping over the Khuff and the Khimar."

A head covering not limited to the common usage of "turban" as is clear from the first narration.
Sunan an-Nasa'i Book 1, Hadith 104
← Previous Hadith "When the believing slave performs Wudu' and rinses his mouth, his sins come out from his mouth. When he sniffs water into his nose and blows it out, his sins come from his nose. When he washes his face, his sins come out from his face, even from beneath his eyelashes. When he washes his hands, his sins come out from his hands, even from beneath his fingernails. When he wipes his head, his sins come out from his head, even from his ears. When washes his feet, his sins come from his feet, even from beneath his toenails. Then his walking to the Masjid and his Salah will earn extra merit for him."

Sunan an-Nasa'i Book 1, Hadith 103 Next Hadith → "I saw the Messenger of Allah (ﷺ) wiping over the Khuff."

Sunan an-Nasa'i Book 1, Hadith 105