Zirr bin Hubaysh heard Sayyiduna Ali (may Allah be pleased with him) when Sayyiduna Ali (may Allah be pleased with him) was asked about the ablution of the Prophet (peace and blessings be upon him) (and he narrated the hadith). In it is: He wiped his head while drops of water were flowing, and washed his feet three times each. Then he said: "This is how the ablution of the Messenger of Allah (peace and blessings be upon him) was."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 265