Industry-Electronics 4duino GSM GPRS Sheeld für Arduino Uno Product Model: OKY2223-2 SIM900 GSM Module 850/900/1800/1900 MHz GPRS/GSM Development Board Module Kit For Arduino Product Description 1.Quad-Band 850 / 900/ 1800 / 1900 MHz – would work on GSM networks in all countries across the world. 2.GPRS multi-slot class 10/8. 3.GPRS mobile station class B. 4.Compliant to GSM phase 2/2+. 5.Class 4 (2 W @ 850 / 900 MHz). 6.Class 1 (1 W @ 1800 / 1900MHz). 7.Control via AT commands – Standard Commands: GSM 07.07 &amp 07.05 | Enhanced Commands: SIMCOM AT Commands. 8.Short Message Service – so that you can send small amounts of data over the network (ASCII or raw hexadecimal). 9.Embedded TCP/UDP stack – allows you to upload data to a web server.