I cannot emphasize enough the importance of harnesses instead of collars for small dogs. There is the most well known reason, that any dog can damage their trachea (windpipe) by straining against a collar, and also because collars, if not fitted exactly right can be very easy for a dog to slip out of, but it is critical to use harnesses for tiny dogs even more than other breeds because there are predators out there!
I have heard of Pomeranians being taken by birds of prey from people's back yards, and in one particular case, while walking on leash. This particular dog was saved by a harness because the owner was able to pull the dog away safely from the hawk. If this dog had been wearing a collar it could have slipped off or seriously harmed the dog if it had been yanked by its neck back to the owner.
While the above is an unbelievably rare occurrence, it is actually shockingly common to have an unleashed big dog come running at your pom from out of nowhere. If your dog is in a harness, you can safely and efficiently pull that dog up into your arms (and if necessary, hold it over your head to keep it safe from strange dogs. A large dog can kill a Pom with one bite, and this is unfortunately a common fate for dogs this small who get attacked by regular-sized/large dogs.
This could happen anywhere; a dog could get out of its yard in your neighborhood, or it could be off leash on a mountain trail or at your local park. A harness is essential to get your dog from the ground to in your hands in a split second, because sometimes that is all the time you have.
