Martingale Collar

This type of collar slips over the head, there is no buckle to open or close. It is most often used for sighthounds (greyhounds, whippets, Borzoi, etc) because their heads are smaller than their neck and they can slip out of a traditional collar. However, it can be used for all breeds of dogs - just remember, if your dog has a big head, you will need to adjust it large enough to slip over the head, then adjust it to the correct size for the neck.

Side Release Buckle Collar

This is a traditional type of dog collar with a side release "snap" buckle that opens and closes. It is the easiest type of collar and what most people are familiar with. You just need to adjust it to the right size for your pup's neck, then put it around the neck and click the buckle closed.

Buckle Martingale Dog Collar

This is a hybrid of the 2 collars above and works well for dogs who have larger heads. It is better for large breeds than for small breeds because the buckle adds in bulk to the collar and offers less adjustability. But for dogs who need a martingale collar for training but have larger heads, this is a good option.