The kryptonite mini messenger with u lock extender has been based on the legendary evolution mini 5 the new messenger mini has a wider and longer shackle which increases the number of places it is possible to lock your bike kryptonite wont release there secret but it still fits in your back pocket too the max performance steel shackle allows for a reduced diameter while maintaining the same security as the mini 5 durability has been increased with the addition of the new duocore cylinder