These wheels are made from a mix of abrasive cloth and abrasive fiber to obtain the exact surface wished by the polisher. The participation of the abrasive fiber has a minimum role in terms of abrasion, its major effect is to be used as an absorber, which will give you a very smooth polishing, but very abrasive during the removal of smudges even on hard metals.
The S/T range is only used for fine grits from 320 up to 1000 grit which will give you a very high quality satin finish.