The Speakman RPG05-0897 is a genuine OEM brass shower valve diverter cartridge designed for Sentinel Mark II (CPV-P-DV/CPV-3400) pressure balance diverter valves and S-1183/S-1183-BN transfer valves. It acts as a repair part to fix, replace, or convert existing Mark II shower trims to newer styles like Neo, Alexandria, Caspian, or Rainier.