Cooper pair
Many overlapping cooper pairs can exist in the same nanometer sized space. Since paired electrons constitute a boson the motions of all of the cooper pairs within a single superconductor synchronise and they function as if they are a single entity. This is known as the Bose–Einstein condensation. The Cooper pairs  form this condensate, which is superfluid or super-conducting.  Small disturbances such as scattering of electrons are forbidden in this state  as long as the temperature remains low.  It moves as one showing no resistance to its motion. It is hence now a superconductor.