Frame locks mount to the bike and provide a convenient immobilizer for easy and quick protection in areas with a low to medium risk of theft . It is recommended to use a secondary lock or the Adaptor Chain/Cable add-on to enable connection to a fixed object. Thanks to the universally adjustable hole spacing, the 6950M can be easily attached to most bicycle frames, including all Priority models with frame lock braze-ons. 8.5 mm thick locking shackle The shackle, the case as well as supporting elements of the locking mechanism are made proprietary, specially hardened steel alloys Accessories (like the Adaptor Chain) can easily be fitted to the locking mechanism on the lock housing ABUS XPlus cylinder for the greatest protection against manipulation such as picking Two keys included with each lock. NR (non key retaining) version allows the key to be removed when lock is open Adaptor Chain/Cable turns a frame lock from a simple immobilizer to a full fledged bike lock that is suitable for higher risk environments and extended periods of time. Use the chain for higher risk environments and the cable for lower and where weight is important. Fits the all Priority models with frame lock braze-ons (found on seat stays) including Continuum Onyx, Eight, E-Classic/Glide, Current Plus, Classic series, and Turi. Does not fit Coast. Questions? Ask us at info@prioritybicycles.nyc