Factory Team precision-ground diff rings
Coming from Associated Electric’s Factory Team brand are precision-ground diff rings for 2.60:1 ball diffs. The precision comes from a flatter, tighter tolerance diff ring that will result in smoother diff operation and longer life, therefore increasing time between rebuilds. The rings are a direct upgrade for #7666 diff drive rings and they fit RC10B4 to B6 series, SC5M and SC6.1, RC10T4.1 to T6.1, and all SC10s buggies and trucks using ball diffs.
Source: Associated Electrics [associatedelectrics.com]