This little but powerful motor is ideal for hundreds of electrical experiments and projects!  The motor housing is 23.8 mm in diameter and 30.5 mm in length with an overall length of 45 mm inlcuding hte 2 mm shaft.  Voltage requirements are 4.5 to 6.0 Volts DC.  Each motor is connected to 30 cm red and black alligator clips with insulators.