This lock housing is a replacement product for the standard M5/M6 locks only. This will not fit solid axle nuts. If you need to purchase a replacement part for a solid axle nut, please purchase the solid axle lock ring instead.
The security ring rotates freely, and secures the coded nut against forcible openings. The cylindrical shape leaves just enough space for the Pitlock key to fit.
Note that this is not a complete locking mechanism, only the housing. For a complete locking mechanism setup, you will also need to order a coded nut, a compression washer (for either a seat post skewer or a wheel skewer), a teflon ring and a lock ring.