Tamiya 70140 Pulley (S) Set
Gearspulleysbushingsbelts   Can you say Science Project? You get the whole shebang (45 pieces) in one plastic set: (30) bushings in assorted thicknesses, (4) 5/16" dia gears, (2) 1-1/8" dia pulleys, (2) 3/4" dia pulleys, (4) 7/16" dia pulleys, (4) 2" rubber-band belts and (1) 40" length of elastic cord. Includes graphic directions. Made to use with small DC motors with 1/16" shafts.