This Advanced Control Knob for Tilta Mirage mounts directly to your Variable Nd or Polarizer Filter in order to provide a more comfortable and precise option for adjusting the density of your filters.The Control Knob attaches directly to these filters via two M3 threads which allows this accessory to be used in multiple situations, even when the filter is mounted directly to the lens via our Lightweight Clamp-On Adapter.This accessory is the perfect solution for anyone who frequently needs to manually control their Variable Nd or Polarizer..