>>1027348Anything but the round style you posted, really. Those were easily exploitable by pens, but most thieves just attack the actual body of the lock. They don't sit there with lock picks like some spy agent.
All locks are breakable, you just want to make it not worth the thieves time and prevent opportunity thieves from easily walking away with your wheels or whatever. Leave a bike somewhere long enough and people will steal everything off of it.
