The kryptonite evolution 4 1090 chain lock with integrated chains are for convenient bicycle protection in moderate to high crime areas the hardened triple heat treated boron manganese steel chains include 10mm six sided links the integrated chains secure with a new patent pending integrated evolution series 4 lock head this innovative series of kryptonite chain locks also feature a patent pending pin less design which secures the chain to a hardened deadbolt and allows for no weak leak in th