AT4 PACKAGE PERFORMANCE AIR INTAKE 6.2L V-8 FACTORY NAVIGATION DUAL POWER BUCKETS HEATED/COOLED SEATS You are looking at a 2021 GMC Sierra 1500 Crew Cab AT4 .It is powered with a 6.2L Vortec V8 and automatic transmission. It is equipped with am/fm/cd player, dual power... via AutoRevo