Musannaf Ibn Abi Shayba 13:1145

Abu Bakr narrated to us, he said: Humayd ibn Abd al-Rahman narrated to us, from Dinar, who said: I said to al-Hasan, "I sell the merchandise and I disclaim [responsibility for] sores, wounds, internal defects, the hidden, and the apparent." He said, "You do not disclaim [responsibility] unless you say, 'In this [item] is such-and-such, and in this is such-and-such.' Otherwise, it is returned to you."