Seeed-GPRS-Shield-with-Antenna-&-External-SIM-Holder-V3-0-Seeed-Studio-113030009-P-The-GPRS-Shield-from-Seeed-Studio-is-an-Arduino-shield-with-quad-b&-support-for-the-850-900-1800-1900 M Hz-bands-&-TCP-UDP-protocols-The-shield-has-a-SIM-socket-&-is-supplied-with-an-external-antenna-Fit-your-SIM-into-the-socket-&-your-Arduino-is-ready-to-send-&-receive-texts-A-library-is-available-on-Github-to-simplify-the-process-P-P-Seeed-provide-technical-documentation-example-projects-and