Sizes are for Miniture dogs
355307
Did not realize the sizes where for much much smaller dogs. I ordered the large, however it was like a small miniture poodle, for a large size. Disappointed.
1226424
For those that are confused with the sizing for your dog, below is the sizing chart from Petsafe.

Consider your dog's weight based on the chart below. Next, look at the shape of the dog's head and snout. Breeds with long slender heads may take a smaller size than other dogs of the same weight. Breeds with wide muzzles may need a slightly larger size. When in doubt, choose the next larger size.

Petsafe Fitting Chart--------------------------------------------------------------------------------

Size --------------- Pet Size-------------- ----------Sample Breeds

Petite------------under 5 pounds-----------Chihuahua, teacup and toy breeds, puppies
Small------------5-25 pounds--------------Beagle, Sheltie, Shihtzu
Medium--------- 25-60 pounds------------ Border Collie, Bulldog, Pug
Large------------60-130 pounds ---------- Boxer, German Shepherd, Labrador Retriever
Extra Large-----over 130 pounds----------Great Dane, Newfoundland, Saint Bernard
--------------------------------------------------------------------------------------------------------

I bought this for my aging mother, who just got a puppy after her long time companion Belgiun Tervuren past away. Now that she is getting older, having a pulling puppy seems to be very hard on her when they walk, so I decided to get this gentle lead for her, since I had great experience with this lead, when my Newfoundland was a young ball of energy. Everyone was complementing on how she would take me on walks.
This lead did wonders, worked like a charm. It was almost funny to see her and what the lead would do. Every time she would try to pull, her face would turn to her side so she ends up looking back, then she couldn't walk forward. It would stop her immediately.

The lead may take time for some dogs to adjust to, just because it goes over the muzzle.
With my Newfoundland she did not like the lead on her face and she would try to take it off while walking sometimes but eventually she did get used to it.
For some you may have to be very patient, but you will get there. If anyone is wondering will it hurt your dog? No it will not. it really is gentle on you and your dog.
Best product I have ever used for pulling dogs, stops them before they can even pull.

If your dog is a squirmish I also recommend having a additional regular collar on for back up,(HOLDING IT VERY LOOSLEY SO THE LEAD CAN DO IT'S JOB) in case of slip offs (sometimes it does happen) until you know it's OK.
2625048
I ordered a large size from this brand, did not fit my dogs. They are more like small....
4404240
I have a 13 lb mini dachshund and I got him size large; these fit him perfectly :-) They fit his arms and cover most of his back
2406861
I was unsure about size, I have 2 small dogs about 10 pounds each.  They range from 12 to 14.5 inches long, 8 inch height, and with shoulder to shoulder about 5 inches. I read other reviews and followed the sizing chart. I initially ordered a small for the Shih Tzu and a medium for the terrier.  I needed a small for both, it is still long on the shih tzu  and a little big around the waist but the Velcro adjustment is great. The pouch that sits on the back for toys or treats is useless To carry toys but it is great because when turned inside out it holds the raincoat, it is the carrying pouch. other raincoats I have had for my dogs in the past are a thicker more durable material, this is very thin almost like a windbreaker. I have not used it in the rain yet But I had run it under water and as you can see in the photo it just beaded off. I attached some photos and you can see in them how long it is.
4867165
I wish the sizing chart reflected inches rather than  centimeters. Also should note these are for small dogs. Returning it cost the same as I purchased it for.
1656547
Fit is a little larger than expected, pay attention to the measurements.  The size small is too big and we have a 25 pound dog.
860471
Great for a puppy but beware of the the sizes- a small is xsmall, a medium is a small, and a large is a medium
1050638
I thought I ordered the bigger size for larger dogs but I am just merging two together. These are perfect for smaller dogs.
498062
An ok size for Chihuahua's and can go into micro-
1034565
tiny. No size was listed. The pups are medium breed, average type, 9 days old and these barely fit around their necks
2933378
This one was too big but the smaller one fit my medium size dog perfect. He weighs 16 lbs.
2127274
I ordered a small for my bichon. But this one is more like a Xsmall . VERY small , probably to small to use on my dog :(
1711977
The small size fit our Bichon Frise. About a 15 lb dog.
1295150
look to be very warm for my little doggies.  I ordered two sets of size 3.  they are too small for the shitzu-poodle but fit really well on the Pomeranian.  the insulation inside is on the pads too.  I was concerned that the cold would transmit through the rubber sole but this should prevent that.  I just ordered a set of size 5's.
2463337
I would recommend looking at the size chart before ordering. It looks good on both dogs and it is easy to put on. Easy to wash as well. I ordered a large for both dogs, one is 16lbs and the other one is 23lbs. The medium would have been better for my 16lbs dog but you can adjust the size with the velcro strap. The best part is that the dogs look cute in their Harness.
4417447
It seems like these are a bit on the small size so make allowances for fluffy animals but other than that, these are perfect.  Easy to put on and take off.  Love the design.