Encore GX with GPS 1 Vehicle Communication System with Roof Radio Antenna without Digital S-Band Audio System 2021, GM Original Equipment Radio Antenna Base (42747533) by ACDelco. ACDelco GM Original Equipment Radio Antenna Bases are the foundation of your vehicle's antenna, and are GM-recommended replacements for your vehicle's original components. The radio antenna base performs several functions: provides the antenna cable connection interface, provides the grounding point for the antenna ground plane, mechanically supports the mast, and seals out water from the vehicle interior. These original equipment radio antenna bases have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.This trustworthy and highly reliable ACDelco product ensures top quality and provides efficient and long lasting operation without any loss of performance.