エンコーダ付 6V 100:1 155RPM マイクロメタルギアモータ

Works as advertised, though it's a shame that all of the encoder options for these micro metal gear motors have the wires coming out vertically rather than horizontally, so one will either lose clearance and have the wires handing down under the robot, or have to (typically) cut a hole in the mounting plate to clear the the encoder board and wires. Coming out horizontally would be quite a bit nicer. (I realise this is feedback to the manufacturer, not RobotShop.)

The same tiny motors that you are used to but with the additional utility of an encoder. Often only a single phase is required for simple projects.

Installed on my Zumo chassis.

Well built little servo motor for price

This is a good product. The board and wire connector helps a lot. The board has an LED to show it is working.