The Ericsson 4415 B1 KRC161 635/1 is a radio unit used in wireless communication systems. It is a 2T2R two transmit, two receive radio unit capable of operating in the 2100MHz frequency band. The unit has a maximum output power of 40 watts, making it suitable for medium to large coverage areas. It is commonly used in 3G and 4G networks to provide voice and data services. The radio unit is designed to be compact and efficient, making it easy to install and integrate into existing network infrastructure.