I saw seventy of As-Suffa men and none of them had a Rida' (a garment covering the upper part of the body). They had either Izars (only) or sheets which they tied round their necks. Some of these sheets reached the middle of their legs and some reached their heels and they used to gather them with their hands lest their private parts should become naked. (Using translation from Bukhārī 442)   

رَأَيْتُ سَبْعِينَ مِنْ أَهْلِ الصُّفَّةِ مَا مِنْهُمْ رَجُلٌ عَلَيْهِ رِدَاءٌ إِمَّا بُرْدَةٌ وَإِمَّا كِسَاءٌ قَدْ رَبَطُوهَا فِي أَعْنَاقِهِمْ فَمِنْهَا مَا يَبْلُغُ نِصْفَ السَّاقِ وَمِنْهَا مَا يَبْلُغُ الْكَعْبَيْنِ فَيَجْمَعُهُ بِيَدِهِ كَرَاهِيَةَ أَنْ تَبْدُوَ عَوْرَتُهُ