Abstract: The disclosure provides an apparatus for substrate polishing, the apparatus includes a housing member, a carrier member, and a distal force assembly. The carrier member is coupled to and disposed radially outward of the housing member. The distal force assembly disposed radially inward of an exterior portion of the carrier member and radially outward of the housing member. The distal force assembly includes a bladder seal, a seal ring in contact with the bladder seal. The seal ring has a seal ring face and one or more grooves disposed therein. The grooves include a plateau radius and a ridge radius disposed opposite the plateau radius at an intersection between the seal ring face and the grooves, wherein the plateau radius and the ridge radius are between about 0.012 to about 0.018 inches. The distal force assembly also includes a transfer ring coupled to the seal ring opposite the bladder.