Abstract: Discloses a torque multiplication device for use in tightening or loosening a nut, lug, bolt head and the like, employing a planetary transmission of sun, planet and orbit gear means which multiplies the applied torque input to produce an output torque to facilitate and simplify such tightening or loosening. Brake means incorporated with the device prevents rotation of the orbit gear means.A modification of the invention discloses an extensible brake arm which has an anchoring socket for securement with another nut, lug, bolt head and the like to likewise prevent rotation of the orbit gear means.Another modification of the invention discloses two sets of sun, planet and orbit gear means having one common, drive output to produce uniform and balanced drive output.Another modification of the invention discloses a ring-like brake arm having a plurality of anchoring sockets for locking securement with the lugs of a motor-vehicle wheel.