"The Messenger of Allah forbade me to wear a ring on this one and this one," meaning the forefinger and middle finger. And this is the wording of Ibn Al-Muthanna.
Sunan an-Nasa'i Book 48, Hadith 172
← Previous Hadith 'Ali said: "The Messenger of Allah said to me: 'O 'Ali, ask Allah for guidance and steadfastness,' and he forbade me from placing a ring on this one and this one' - and he pointed to his forefinger and middle finger.

Sunan an-Nasa'i Book 48, Hadith 171 Next Hadith → "The Messenger of Allah said to me: 'Say: O Allah, guide me and make me steadfast,' and he forbade me to put a ring on this one and this one" - and Bishr (one of the narrators) pointed to his forefinger and middle finger. And 'Asim said: "One of the two of them."

Sunan an-Nasa'i Book 48, Hadith 173