We will describe the expected performance of the AMR-C radiometer on the Sentinel-6 mission. The AMR-C includes two key evolutions from the radiometer on the Jason-3 mission. The first is a special blackbody calibration system that is viewed by the radiometer approximately every 5 days and promises multi-year stability at the sub-mm level. This, in part, will reduce uncertainty on the global mean sea level trend derived from the Sentinel-6 mission. The other improvement is the high-resolution microwave radiometer (HRMR) which is an experimental payload that provides cm-level path delay measurements within 5km from land. We will describe the expected performance of these systems and plans for post-launch calibration.