Gear box set is brand new, never opened. I purchased 3 for a test I was running and never made it to the last set. You can assemble the gear box to several speed ratios. I built the maximum and it was so powerful you could never stop it with your hand, or any tool for that matter. This thing is wicked strong. Is a fun toy to build science experiments or to use with Lego's or an erector set. It is even fun to build and learn how the planetary gear system works. Great learning tool to build with children and understand electricity, gears and work. Heads up, the life cycle test I ran on the other 2. The motor brushes will last about 400hrs at continuous usage and over 1000hrs intermittent before they need replaced..