Sahih Muslim Book 7, Hadith Number 2871.

Chapter : Clipping of hair in ‘Umra.

Ibn Abbas (Allah be pleased with him) reported that Mu’awiya b. Abu Safyin had told him: I clipped the hair (from the head of) Allah’s Messenger (may peace he upon him) with a clipper while he was at al-Marwa, or I saw him getting his hair clipped with a clipper as he was at al-Marwa.1722