A no-pull harness, by definition, is a harness that discourages your dog from pulling. Most no-pull harnesses work by changing the point of leverage between you and your dog. They are designed so that every time your dog tries to pull ahead, the harness shifts their direction towards you.
By contrast, a regular harness allows your dog to pull, and may even encourage pulling.
There are two primary kinds of no-pull harnesses. The first is the standard front-clip harness where the leash is clipped to your dog’s chest area. Front-clip harnesses are usually used for loose-leash walking, like an afternoon walk in the park or trip to the store. Most are not suggested for running or jogging however, as they can get tangled with your dog’s legs when he is in stride, risking injury. Front-clip no-pull harnesses can come in a variety of styles and colors, some with simple nylon straps and others with padded webbing, or a reinforced chestplate.
There's a front-clip and back-ring harness. Like the front-clip harness, it has a clip that connects the lease to the dog’s chest. But it also has a back-ring connection, usually sold with a double-sided leash. Kind of like the reins on a horse, this allows you to steer your dog and can be a useful training tool for particularly excitable dogs. However, these harnesses are also more restrictive and generally considered less comfortable for your dog.
The general rule is to use a front-clip and back-ring for serious pullers, then to graduate to just the front-clip, and finally back to a regular harness or flat collar for daily walks.
Needless to say, if you have a puller (and especially a large breed dog), you should stay away from regular, back-clip harnesseses, like those sold at your local Petco or Petsmart. Although they are the most common and versatile kinds of harnesses, they do nothing to prevent your dog from pulling. Because normal harnesses are designed to rest on the most powerful muscles in your dogs body (those across his chest and shoulders) it is easy for your dog to pull against them, and may contribute to his bad behavior long-term.
An ideal no-pull harness is a thick and durable one. Thin harnesses can more easily damage a dog’s skin, especially a small and hairless one. Thick harnesses, on the other hand, distribute the pressure more evenly and are usually more resistant to pulling pressure. This is the same effect used in prong collars and fur saver collars, where the rule is "the thicker the collar, the milder the effect."
If you're concerned about the effects of a thin no-pull harness, you can opt for a padded or reinforced no-pull harness. This extra layer of cushioning or webbing can make a world of difference to your dog, who may be too distracted by the pressure applied by a thinner harness for it to even help! If you've tried a no-pull harness on your dog before and he didn't like it, it's worth considering a padded no-harness instead, as many dogs will have no trouble with these once they're acclimated.
Some harnesses are made of padded air mesh which makes the harnesses breathable. This makes them more comfortable to wear especially during long walks. If you're in a very wet climate, you should also look for weatherproof material. Some designs even have reflective straps to give your dog more visibility when walking during the night.
There is a wide variety of no-pull harnesses available in the market. Thus, your puppy will surely find something that works perfectly for their size. A right fit is very important for the harnesses though, as they should not be too tight or too loose to ensure your dog’s comfort. If a harness you bought does not fit your dog perfectly, consider buying another one or getting it altered.
Of course, you should not settle for just buying a no-pull harness to fix your dog’s pulling problems. Train your dog to stop pulling or get a trainer to do it. The best kind of no-pull harness is one that you don’t have to use.