There’s also an SD card thrown in for good measure, making this one of the best tracking and data logging shields for the Arduino.

It is an Arduino compatible board (hardware, not footprint) based on the ATMEGA1284P which can be programmed to collect and post data to internet logging sites such as Thingspeak or Xively.

The GSM Shield also includes a Telefonica SIM card that includes a worldwide data tariff which can be used anywhere there is a cellular signal.