Hopefully, I never have to find out whether these are affective or not, so I can only comment on the concept.  You can either tie two things to a stable, heavy object such as a big desk, or you can tie three pieces of hardware together (such as in the picture) and make it a pain in the behind for someone to take all three at once and walk out your door. Of course, none of that matters if the person knows you have the cable and brings a snazzy pair of bolt cutters.  I haven't seen a product like this before, so I was thrilled to install it (it took 5 minutes); it's a better deterrent than the more popular kensington slot locks but will leave a gray lock on whatever you put it on, so choose wisely.  In the end, as with most inexpensive security devices, it's really about the piece of mind, rather than the effectiveness of the product.  If you want more, you can dish out some extra green and get you one of them "MI2" laser systems.  Cool.