Wide varieties of collars exist. Leather collars are nice, strong and sturdy, but they do pick up smells and if they get wet, they may become brittle or start to rot. The rolled leather variety avoid the chafing or hair breakage that flat collars sometimes do to dogs.
Metal link 'choke' chains are not recommended except for correction training where the techniques must be learned and applied correctly.
Halter style collars act on the nose preventing a strong dog from pulling. Similar to chains you do not leave these collars on unattended dogs.
Harnesses are useful if your dog is small or delicate, using a harness instead of a collar when walking will avoid neck injuries. Be sure the harness fits comfortably and will not chafe the armpits. You will probably want to use the harness for walking and still have a normal collar for the tags. If you have a big dog that likes to pull, getting a harness will only improve pulling power.
Wireless collars are not recommended because they always destroy your dog's confidence and well-being.
We like a flat buckle or quick release collars of nylon that fit properly. Take care not to pinch the dog's skin with these or your best friend will have an 'anxiety' moment every time you put them on.
Leads or leashes also come in many varieties. The popular flex-lead is spring-loaded and quite long allowing your dog some freedom to roam. We recommend a rope lead with a spring hook and a simple rope lead for retriever training and working tests when a collar is never worn for safety.