كتاب البيوع
7  
Business Transactions
Muslim has:
"He has three days in which to decide to keep them or not."
وَلِمُسْلِمٍ: { فَهُوَ بِالْخِيَارِ ثَلَاثَةَ أَيَّامٍ } 1‏ .‏


‏1 ‏- مسلم ( 1524 )‏ ( 24 )‏.‏

Sunnah.com reference : Book 7, Hadith 41
English translation : Book 7, Hadith 0
Arabic reference : Book 7, Hadith 814