M5Stack Communication Modules are stackable multifunctional LTE communication modules with a built-in LTE communication module SIM7600G. They support LTE-TDD/LTE-FDD/WCDMA and GSM frequency bands, LTE.CAT4 (downlink speed is 150Mbps), voice calls SMS with SMS. The modules have stable performance, small appearance, high-cost performance, and can transmit SMS and data information with low power consumption.