Self-locking nut

Listed on the following equipment:
Technogym - 700 JOG NOW - DAK31L
Technogym - DAK3AV - DAK31V - 0.2
Technogym - Spin Trainer - D250U
Technogym - Top 700 - D4773L - (SN D4773L08000161 - Below)
Technogym - Top 700 - D4773L - (SN D4773L08000162 - D4773L08000362)
Technogym - TOP Upper Body Trainer - DA7 - (DA773W)

* Images may not be identical to part.