The base shield provides a simple way to connect to Arduino boards, without the need for breadboards and cables. With the 16 built-in Grove Connectors, you can easily connect any available Grove modules to the board There are 16 built-in Grove connectors that include. In addition to the Grove connectors, the board also features an RST button, green power status LED, ICSP pin, toggle switch and four rows of pins Each Grove connector has four wires, one of which is the VCC. However, not every microcontroller main board needs a 5V power supply voltage, some boards only need 3.3V. The inclusion of a power switch means that you can select the appropriate voltage of the microcontroller main board you are using via this switch Features: Offers a simple way to connect to Arduino boards, such as the Arduino UNO, without also needing a breadboard and cables The board features an RST button, a green power status LED, an ICSP connector and four rows of connectors. It has a 3V/5V power switch, allowing use with Arduino 3V and 5V compatible boards There are 16 built-in Grove connectors, including: 4x Analog 7x Digital 1x UART 4x I2C