As you rotate the a/s device on the junction box, it can provide the greatest a/s force to be set variably... As the cartridge moves across the record, skating force changes...some say the greatest force is at the end of the record (the loudest usually), some say its at the beginning where the record is really moving under the arm faster than at the end, and some think the middle of the side is the best solution. The VPI a/s device enables the user to adjust where the greatest force is by the a/s rotation clockwise/counterclockwise on the junction box. When the little a/s arm is at its most horizontal position, the greatest force is applied, when the weight of the little arm is gradually supported by its pivot, the less a/s force is applied. My cartridge tracks perfectly well (no sibilants at all with any record I own) with no a/s. Cartridges do their best when adjusted properly...a very time/patience consuming activity.