It wasnarrated from Ibn 'Umar:
"The wives of the Prophet (ﷺ) wereallowed to let their hems hang down, so they used to come to us andwewould measure one forearms length for them with a reed." (PT)
English reference (PT): Vol. 4, Book 32, Hadith 3581 (PT)
Arabic reference (PT): Book 32, Hadith 3712 (PT)