Greartisan DC 12V 27RPM Worm N20 High Torque Speed Reduction Motor with Metal Gearbox Motor for DIY RC Toys

This is definitely not a 12v motor. I bought the 3V version and a 12V version and they are the same. They have very low torque. Running these at 3V for some robot wheels may be fine, but if you actually need to move anything with a little bit of weight good luck. (Couldn't slowly spin a Raz Pi5 and a web cam even at the 16-30 RPM range).

I submitted a question asking how I could mount this motor and gear box to a plate. After doing some research I found that if you do a search for "N20 motor mount" you will find motor mounts that are made specifically for all implementations that use this size (12mm) motor. Hope this helps everyone interested in items using N20 motors. Other than that, the motor and build quality appear very good. I did a test run and the motor and gear box were quieter than I expected.

no noise, great gears, torque ,speed is great

Overall this seems like a handy little gearbox. Runs smooth and quiet. Others have complained about torque but it seems ok in my particular application. The thing that bothers me personally the most is that the output shaft has the flat the full length. Now I can't seal it with an o-ring, and there's no great reason to have a full length flat. If you guys update this motor or can do a custom one please make that simple change to improve the result. That mounting complaint is valid too, but not that big a deal. You could use some long 0-80 screws if you really wanted to, or drill your own. (like I'm going to have to fabricate my own shaft now).

Sturdy metal structure, holds together and can move good sized robots.