If the security of your bike is of the utmost importance for you, then the XLC U-Lock Sundance and Cassidy III LO-S05 is the obvious choice for thief proof protection. The LO-S05 features an X2P double bolt as well as a Z cylinder, including BumbBlok. The lock barrel is also protected against breaking and drilling, some of the most common methods used by bike thieves, so you can be sure your bike is safe when parked up outside. As well as a sturdy lock barrel, the U bar is constructed of hardened steel and coated in a rugged double-coated rubber, helping further prevent its vulnerability to cuts. The SnapLock quick release bracket allows for a quick lock up, and the LED key and four precision keys give lots of unlocking capabilities. Security level 8 should give you peace of mind with this outstanding U-Lock.