Its steel shell has no obvious weak points that say "Cut here!" and its lock is so resistant to picking that even Disklok owners report having to do some key wiggling to get it to unlock (which is actually an intentional safety feature). Its weight and size make it less convenient to carry with you than some of the other locks we studied, but it outperforms the competition when it comes to security.
The Disklok isn't without its weaknesses—we saw a guy with a metal grinder cut it off in about three and a half minutes. But in car theft time, that's pretty long, and using power tools would be noisy enough to draw quite a bit of attention.
Because the Disklok is different from most normal bar-style steering wheel locks, it takes longer to figure out, so it's a good deterrent. With manual tools, it would be impossible to remove. Just make sure you select a Disklok device that's the right size for your steering wheel, because if it's too snug it won't work correctly.