Diymall Itead Raspberry PI SIM800 GSM/GPRS Add-on V2.0 NOTE: T-Mobile only,as AT&T phased out all 2G service January 1, 2017 Quad-Band 850/ 900/ 1800/ 1900 MHz GPRS multi-slot class 10/8GPRS mobile station class B Low power consumption: 1.5mA(sleep mode) If you want to buy board which can work for for USA 3G network, here is the link: https://www.amazon.com/dp/B06Y3N1BD6