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" (RU)
English reference (RU): Book 10, Hadith 71 (RU)
Arabic reference (RU): Book 11, Hadith 75 (RU)