Chain bike locks

Chain lock

— locks in the form of a chain, the ends of which can be closed into a ring with a lock. Considered one of the most reliable varieties, a high-quality model is second only to the U-lock in terms of burglary resistance (see the relevant paragraph), while the chain lock is longer and provides more fastening options (although it is still less versatile than a cable lock). The main disadvantages of such devices are bulkiness and significant weight.