Saaib bin Yazid reported,

My maternal aunt took me to the Messenger of Allah ﷺ and said, "Messenger of Allah, my nephew is ill."He wiped my head and prayed for blessing upon me, then he performed ablution, and I drank from the water of his ablution. Then I stood behind his back and looked at the Seal of Prophethood between his shoulders, resembling the Zirr of a bridal canopy.

Azami 9466

Sahih

عن السائب بن يزيد قال

ذهبت بي خالتي إلى رسول الله ﷺ فقالت: يا رسول الله، إن ابن أختي وجع فمسح رأسي، ودعا لي بالبركة، ثم توضأ فشربت من وضوئه ثم قمت خلف ظهره فنظرت إلى خاتمه بين كتفيه مثل زر الحجلة.

الأعظمي 9466صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Biography of the Prophet ﷺ
Chapter
Character of the Prophet ﷺ
Section
Characteristics of the seal of prophethood and its location on his body
Numbering
Jami al-Kamil 9466 (2nd edition)
Azami 9466