Arduino-GSM-Shields-for-Wireless-Communication-Arduino-A000106-P-Send-&-receive-SMS-messages-from-your-Arduino-with-the-GSM-Shield-2-or-make-&-receive-phone-calls-or-even-surf-the-net-Plug-this-neat-little-board-into-your-Arduino-add-a-SIM-&-you-are-ready-to-begin-The-board-is-open-source-giving-you-acces-to-the-schematics-&-its-free-GSM-software-library-This-version-of-the-board-has-a-connector-for-an-external-aerial-another-version-is-available-which-has-an-on-board-aerial-