I heard Ibn 'Abbas deliver a Khutbah from your Minbar - meaning the Minbar in Al-Basrah - saying: 'Sadaqatul Fitr is a Sa' of food." (Sahih) Abu 'Abdur-Rahman (An-Nasa'i) said: This is the most reliable of the three.
Sunan an-Nasa'i Book 23, Hadith 76
← Previous Hadith Ibn 'Abbas said concerning Sadaqatul-Fitr. "A Sa' of wheat, or a Sa' of dates, or Sa of barley, or a Sa' of rye." (Sahih Mawquf)

Sunan an-Nasa'i Book 23, Hadith 75 Next Hadith → "The Messenger of Allah enjoined Sadaqatul Fitr, a Sa' of barley or a Sa of dates or a Sa' of cottage cheese."

Sunan an-Nasa'i Book 23, Hadith 77