Abus Granit Plus 640
The U-lock is classic when it comes to securing bikes, and for good reason. Solid materials and no moving parts outside the lock mechanism are an excellent starting point for the strongest resistance possible. Decades of experience with the U-lock have made ABUS experts in combining the most resistant materials with unique technology, and consequently one of the leading U-locks manufacturers. By the way: the police and insurance companies recommend the use of a U-lock.
The Abus Granit Plus 640 9" U-lock has has a locking room of 9" x 4", making it easy to fit around your bike and a rack, while remaining at a much lighter weight than run-of-the-mill U-locks. Frame mount included. Security rating 12/15.