Another fact about the marvellous green dog collar is that most people use them ineffectively because they are not that easy to use and there are some secrets that the old time professionals used to make them more effective and the correction stronger. First, these professionals make sure the length is right or you won't get the strong, quick pop. If the chain’s too long, when you go to give a correction, there’s too much slack. When it's too short, the collar tightens too quickly, before you’ve gained enough momentum in the jerk. Seasoned trainers also know that dog's feel the correction more if you can keep the marvellous green dog collar up high, right behind the ears. That’s how Cesar Milan’s Illusion collar works. It keeps the collar positioned so that a correction can have the greatest effect (e.g. create the most effective jerk). Back when I was competing in obedience we didn't have Illusion collars and they wouldn't be allowed in the ring now anyway, but we did try to keep that marvellous green dog collar up high when we were training. A third point, but one that’s the first thing a seasoned professional trains is that the marvellous green dog collar has to go on the right way. It needs to form a “P,” with the tail of the “P” on the same side as the handler. You can tell right away when a force-based trainer isn't good at his marvellous green dog collar technique because he doesn't even put the collar on correctly.
So there you have it, an overview of a variety of common collars and harnesses. None is perfect. They are all just tools. But some are more likely to cause problems in your pet or may just provide a less than ideal match for your needs. In case you're wondering which I prefer—ideally my dog can walk on leash with the flat collar he wears regularly. But for those dogs that tend to pull and need more work, I tend to recommend a front-attaching harness or a head collar of some sort.