Line 6 Helix (LT) original jack nut

thingiverse

The standard issue jack nut used on a Line 6 Helix processor features six notches cut into its outer circumference. This design allows users to easily turn the nut counterclockwise until it is completely removed from its threaded post. The resulting gap provides access to the post's interior, where technicians can install or replace the processor's circuit board as needed.