A tool for installing a blind fastener including a core bolt and a core nut is provided. The tool includes a driving member, a collet driven by the driving member for engaging the core bolt, and an external sleeve for holding the core nut and preventing the core nut from rotating during installation of the blind fastener. The external sleeve is movable between a first position in which the external sleeve is driven by the collet to rotate with the collet and a second position in which the external sleeve is stationary despite rotating action of the collet.