Collars

Your basic training collar will be a buckle or quick-snap collar. Every dog
should have one. You will attach any tags and identification. This is the only
collar that is safe to leave on your dog when he is alone. Try to do as much of
your training as possible on this collar.
A disadvantage of buckle collars is that some dogs can back out of them.
This is dangerous if you are walking on a street. For this situation, I recommend
a martingale type collar. A popular brand is a Premier collar. This type
of collar closes enough to prevent your dog from escaping, but not enough to
choke your dog.
When it comes to teaching your dog not to pull on leash, you may find
it useful to use something other than a buckle collar. There are several to
choose from, all of which work by making your dog uncomfortable when he
pulls.

Prong collar, nylon choke collar, buckle collar, martingale collar.

My favorite is a head collar. Some popular brands are the Gentle Leader
and Halti. Head collars work by pulling a dog’s head to the side when he
pulls forward. These are very humane and the most effective way to stop
pulling on leash. Head collars have a strap that goes around a dog’s neck and
another that goes around his muzzle. They work like a halter does on a
horse. If a halter can control a thousand-pound animal, it can control the
largest Newfoundland, the most headstrong Lab, or the most stubborn terrier.
Head collars are great for working with dogs who lunge for any reason,
whether to jump on people or chase squirrels, or because of aggression problems.
They can make trips to the vet much less stressful.