Cable, Within a series of overlapping sleeve segments .. Abus Locks are Best, ABUS Steel-O-Flex - Locks / Bike Safety and Security
ABUS Steel-o-flex 1025/100 (33561)


I Use their Bordo Type a folding Link lock http://www.abus.com/us/Recreational-.../Folding-locks and their chain Locks with a Built in Lock http://www.abus.com/us/Recreational-...in-Combination

I own an armored cable type lock from OnGuard , and Specialized, bought earlier, too..