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.'"
English reference: Vol. 1, Book 1, Hadith 227
Arabic reference: Book 1, Hadith 228