حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَعَلِيُّ بْنُ مُحَمَّدٍ، قَالاَ حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ هِشَامِ بْنِ حَسَّانَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ ـ صلى الله عليه وسلم ـ قَالَ ‏"‏ مَنِ ابْتَاعَ مُصَرَّاةً فَهُوَ بِالْخِيَارِ ثَلاَثَةَ أَيَّامٍ فَإِنْ رَدَّهَا رَدَّ مَعَهَا صَاعًا مِنْ تَمْرٍ لاَ سَمْرَاءَ ‏"‏ ‏.‏ يَعْنِي الْحِنْطَةَ ‏.‏

It was narrated from Ibn 'Umar that the Prophet (PBUH) said: "O Allah, bless my nation in their early mornings.". It was narrated from Abu Hurairah that the Prophet (PBUH) said: "Whoever buys a Musarrah, he has the choice (of annulling the deal) for three days. If he returns it, then he must also give a Sa' of dates, not Samra'." Meaning wheat. Translation Not Available

Book Ref: Sunan Ibn Majah Book 12 Hadith 2238
Web Ref:  Sunan Ibn Majah Vol 3 Book 12 Hadith 2238