Secures the front wheel solid axle of the Shimano hub dynamo by using a M9 x 1 thread. There is a closure for the left & the right side each.2 closures M9 x 1, 1 Pit key for solid axles, 1 code card The protruding thread is supposed to stick out of the dropout for Approx. 14mm. The locking ring requires a space (supporting surface) of 15 mm in the radius or rather 30 mm in the diameter around the thread, so that the Pitlock lock can be installed safely.