You can find all the replacement parts and accessories you need for your Orbea bike at Escapa, such as the Orbea Occam 24 Rear Axle Nut (6mm Allen).
Removable rear axle Levo for through-axle wheels on Occam 2024 frames.
On LT models, it can also be used to loosen the top screw on the Quick Flip mechanism and adjust the geometry.