This is an Ebyte E28-2G4M20S wireless module SMD (surface mount device). It is 15.0x26.5mm (LxW), has an RoHS compliance, and is designed for use in a wide range of electronics. It is a 2.4GHz, 130Mbps, 20dBm (100mW) transmitter with an onboard antenna. Its Enhanced Low Power Radio (ELP-UNMC) design allows for ultra low power consumption, which maximizes battery life. Its low power standby mode provides an improved link budget. The module supports the UART, SPI, HSPI, I2C, and I2S interfaces. It also has a host wakeup function to reduce power consumption even further. This module is perfect for applications where long range, long battery life, and low power consumption are needed.