Ibn ‘Abbas said God’s messenger’s sandal had two thongs, their straps being doubled. Tirmidhi transmitted it.

عَنِ ابْنِ عَبَّاسٍ قَالَ: كَانَ لِنَعْلِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قِبَالَانِ مُثَنًّى شراكهما. رَوَاهُ التِّرْمِذِيّ