Diamond ACI & ACII Polishing Paste Set: 4 gm Syringe Diamond ACI & 4 gm Syringe Diamond ACII. Aluminum oxide-based pastes - ACI with approx. 80 microns, and ACII with approx. 30 microns. ACI Medium Grit and ACII Fine Grit formulas combine lubricant properties of Carbowax and high-hardness abrasives. The ACI paste is indicated for initial finishing of the surface and ACII paste is indicated for preliminary polishing of resins and other restorative materials.