866
But first they would need to invent some tape
(i.imgur.com)
They could have fitted the whole ring / tape / mouse assembly into a small paper bag Aragorn could have kept it in his jacket and fed it little bits of lembas on the way how lovely x
But that mouse would have become more powerful than you could possibly imagine.
And would sing 🎵 HERE I COME TO SAVE THE DAY! 🎵
Mighty mouse. Faster than a bullet and stronger than a locomotive.