It was narrated that Musa Al-Juhani said:
"A vessel was brought to Mujahid, which I estimated to be eight Ratls, and he said: 'Aishah told me that the Messenger of Allah (ﷺ) used to perform Ghusl using such a vessel.'" (RU)
English reference (RU): Vol. 1, Book 1, Hadith 227 (RU)
Arabic reference (RU): Book 1, Hadith 228 (RU)