YZ250 TITANIUM M16 x 1,5mm Ganzmetall Kontermutter. YZ125 Schwingenmutter
YZ125 swingarm nut. Integrated locking tabs at the top of the nut just like the original OEM part. Yamaha part number:956171610000 NUT, U (6TD). Titanium is more corrosion resistant than Stainless Steel.