The 180 Grit are the orange brushes, and the blue are a 120 grit, if I remember correctly. I use mostly the orange. The paint comes off in fine dust, so a dust mask or respirator will be needed, but a shot from the air nozzle, and your part is clean, and ready for prep sol and paint. The brushes will leave a good surface for the paint to bond to the metal, (just enough scratch). The brushes are hard on drills. The side load does tend to wear out bearings faster than normal. A cheap drill last as long as an expensive one. I usually get two to three complete Heeps per drill, depending if it was a military Jeep or civilian... Or how many coats of paint are to be removed.