The potentiometer twig produces analog output between 0 and Vcc (5V DC with Seeeduino) on its D1 connector. The D2 connector is not used. The angular range is 300 degrees with a linear change in value. The resistance value is 10k ohms, perfect for Arduino use. This may also be known as a rotary angle sensor.
For all Grove users (especially beginners), we provide you guidance PDF documents. Please download and read through Preface - Getting Started and Introduction to Grove before your using of the product.