420006 Geared pager motor

81:1, 454RPM, 20mA (220mA stall) at 6V gives 3.17in*oz torque. Not bad, eh? And only available from Solarbotics !

These little gear motors measure 20.8 x 29.0 x 25.4mm (0.82 x 1.14 x 1.00") and weigh in at 4.7g (0.17oz). The square output shaft measures 3.56mm (0.14") per side, and the leads measure 5cm (1.95") long.

They're a bit funky in that they're not continuous rotation by default. They have a self-centering spring, so applying DC power will result in a 60 degree swing in one direction. Reversing power swings the output arm 60 degrees the other way. Remove the self-centering spring and clip the stops, and away you go!