"I have not seen anyone with hair past his shoulders in a red Hullah more handsome than the Messenger of Allah (ﷺ). He had hair that would flow on his shoulders, (and he had) broad shoulders (and he was) not too short and not too long." [Abu 'Eisa said:] There are narrations on this topic from Jabir bin Samurah, Abu Rimthah, and Abu Juhaifah. This Hadith is Hasan Sahih.
حَدَّثَنَا مَحْمُودُ بْنُ غَيْلاَنَ، حَدَّثَنَا وَكِيعٌ، حَدَّثَنَا سُفْيَانُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ، قَالَ مَا رَأَيْتُ مِنْ ذِي لِمَّةٍ فِي حُلَّةٍ حَمْرَاءَ أَحْسَنَ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم لَهُ شَعْرٌ يَضْرِبُ مَنْكِبَيْهِ بَعِيدُ مَا بَيْنَ الْمَنْكِبَيْنِ لَمْ يَكُنْ بِالْقَصِيرِ وَلاَ بِالطَّوِيلِ . قَالَ أَبُو عِيسَى وَفِي الْبَابِ عَنْ جَابِرِ بْنِ سَمُرَةَ وَأَبِي رِمْثَةَ وَأَبِي جُحَيْفَةَ . وَهَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .
Tirmizi
The Book on Clothing • Hadith 1775