Al-Ala' said: I saw Sayyiduna Qays bin Sa'd bin Ubadah (may Allah be pleased with them both); he urinated, then came to the Tigris, performed ablution and wiped over the upper part of his khuffs (leather socks) like this, and I saw the marks of his fingers on the khuff.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1394