Sunan an-Nasa'i 117
It was narrated that 'Ubaid bin Juraih said:
"I said to Ibn 'Umar: 'I see you are wearing Sibtiyyah sandals, [1] and you performed Wudu' in them.' He said: 'I saw the Messenger of Allah (ﷺ) wearing then and performing Wudu' in them.'"

[1] Made of hairless, tanned leather.
أَخْبَرَنَا مُحَمَّدُ بْنُ الْعَلاَءِ، قَالَ حَدَّثَنَا ابْنُ إِدْرِيسَ، عَنْ عُبَيْدِ اللَّهِ، وَمَالِكٍ، وَابْنِ، جُرَيْجٍ عَنِ الْمَقْبُرِيِّ، عَنْ عُبَيْدِ بْنِ جُرَيْجٍ، قَالَ قُلْتُ لاِبْنِ عُمَرَ رَأَيْتُكَ تَلْبَسُ هَذِهِ النِّعَالَ السِّبْتِيَّةَ وَتَتَوَضَّأُ فِيهَا ‏.‏ قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَلْبَسُهَا وَيَتَوَضَّأُ فِيهَا ‏.‏