Micro Continuous Rotation Servo Motor (FS90R)
Price in Singapore Dollars, including 7% GST of $0.52
The FS90R is a micro-sized servo built specifically for continuous rotation. At 6V, it has a maximum rotation speed of around 130 RPM (no-load) and can produce up to 21 oz-in (1.5 kg-cm) of torque. It works at lower voltages too with the Arduino and micro:bit.
The servo can be controlled using a direct connection to a single microcontroller I/O line without any additional electronics, which makes it a great miniature actuator for beginner robotics projects; just throw on a pair of wheels and your robot is ready to roll!