Self-locking nut

Listed on the following equipment:
Technogym - 700SP SYNCHRO - DA534L
Technogym - Abdominal - M883
Technogym - Chin/Dip - M987
Technogym - Chin/Dip - M987
Technogym - Forma Line - Cross Forma D75
Technogym - New Recline Excite Visio
Technogym - Posterior ME10/ME20
Technogym - RE1 New Recline 700 New Seat - DAD (DAD33W)
Technogym - Rotex 600 XT Pro - D375
Technogym - Rotex 600 XT Pro - D375C
Technogym - Rotex 600 XT Pro - D375CU
Technogym - Rotex 600 XT Pro - D375U
Technogym - Rotex 600 XT Pro - D377
Technogym - Rotex 600 XT Pro - D377C
Technogym - Rotex 600 XT Pro - D377CU
Technogym - Rotex 600 XT Pro - D377U
Technogym - Rotex 600 XT Pro - D380
Technogym - Rotex 600 XT Pro - D380C
Technogym - Rotex 600 XT Pro - D380CU
Technogym - Rotex 600 XT Pro - D380U
Technogym - Rotex 600 XT Pro - D385
Technogym - Rotex 600 XT Pro - D385C
Technogym - Rotex 600 XT Pro - D385CU
Technogym - Rotex 600 XT Pro - D385U
Technogym - Spin Trainer (D250U)
Technogym - Step XT (D230U)
Technogym - Step XT (D231U)
Technogym - Synchro 2009 - DA5 (700)
Technogym - Syncro - 500 - 2009 - Silver (DA523L)
Technogym - Top XT (D270U)
Technogym - Top XT (D271U)
Technogym - Vario 700 DAF73L

* Images may not be identical to part.