These tools are for exquisite fossil preparation. The number 1 & 2 are used for the most delicate of delicate work, specifically under a microscope. They are very light weight and do not blow air on your fossil. The Micro Jack 1 is made to lock into place so it does not rotate. It is the lightest, most accurate and precise tool that we make.
Then we have the Micro Jack 3, 4, 5, & 6, as the numbers get larger so does the volume of air driving the stylus, which translates into more power. The Micro Jack 6 is a good degree gentler than the Paleo Aro however it still has a good matrix removal rate.