The Electron 3G Kit is a tiny development kit for creating 3G cellular-connected electronics projects and products. It comes with a Particle SIM card with service in more than 100 countries worldwide. All Particle Hardware is designed from the ground up...

Waveshare 13460 - GSM/GPRS/GNSS/Bluetooth HAT for Raspberry Pi, Based on SIM868 This is a handy, low power Raspberry Pi HAT which features multi communication functionalities: GSM, GPRS, GNSS and Bluetooth. It allows your Pi to easily make a telephone...

Note - This product is not compatible with the Raspberry Pi 4 (unless using a GPIO extension) WARNING: This HAT works on 2G GSM network which is shutting down in the USA over the course of 2020 and beyond, so please be aware these are not for long term...