Self-locking nut

Listed on the following equipment:
Technogym - 700 JOG NOW - DAK31L
Technogym - 700SP SYNCHRO - DA534L
Technogym - DAK3AV - DAK31V - 0.2
Technogym - Element Multipower - MB83
Technogym - Leg Press - M951
Technogym - Leg Press - MB50
Technogym - ROTARY TORSO - M950
Technogym - Run 600 XT Pro
Technogym - Run XT - D240U
Technogym - Run XT - D241U
Technogym - Run XT - D242U
Technogym - Run XT - D243U
Technogym - Step XT - D230U
Technogym - Step XT - D231U
Technogym - Synchro 2009 - DA5 (700)
Technogym - Syncro - 500 - Silver - (DA523L)
Technogym - Vario 700 DAF73L

* Images may not be identical to part.