These polishers are characterized by the motion of the head. It spins on a central spindle, but unlike an orbital polisher, this spindle rotates around an eccentric offset. A good metaphor is the earth’s orbit. The earth itself spins and it also orbits around the sun.
On a polisher, this produces a jiggling motion. This irregular motion prevents the polisher from burning the paint, which refers to removal of paint below the clear coat surface. Dual action polishers are very USER FRIENDLY as a result of this feature.
The same safety feature which reduces the possibility of damage from a dual action polisher also prevents it from removing deep scratches. While a dual action polisher will improve the appearance of scratches and remove light swirls, it cannot cut or damage the paint.
If you need more thorough scratch removal, this will require a rotary (circular) polisher. Keep in mind, rotary polishers in inexperienced hands can damage the clear coat and run the risk of a serious PAINT BURN. Always start with a safe dual action or random orbital machine before progressing to a circular polisher.
On the plus side, dual action polishers will improve the texture and luster of automotive paint with minimal risk. They are the most user-friendly option and they consistently produce beautiful results. For regular paint polishing and maintenace, a dual action polisher is all you need.