The variable speed foot pedal is awesome for detailed carving and engraving. It allows you to vary the amount of air getting to your tool in order to lower the RPM in very delicate areas, or fast RPM for normal carving and engraving. You no longer have to look up from your work to adjust the regulator in order to change the RPM. This foot pedal is round so your foot is not stuck an any one position, no matter where you press on the pedal, it works! This is a high quality variable speed foot pedal to save you time and effort.