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