Qataadah radiallahu anhu reports that:
"I asked Anas to describe the shoe of Rasulullah Sayyidina Rasulullah sallallahu alaihe wasallam". He replied: "Each shoe had two straps" (FR)
English reference (FR): Book 10, Hadith 71 (FR)
Arabic reference (FR): Book 11, Hadith 75 (FR)