have tried many collars in this price range. My first requirement was the size. Most regular size collars are way too heavy for an under 10 lbs dog. Searching for “small breed bark collars” here on amazon is very misleading, because many sellers will write something along the lines of “bark collar for small medium and large dogs”! You order them, and they’re huge! This one is legitimately the smallest collar I found through several years of buying and returning. The box is barely an inch in length! If you have a chihuahua or a pom, or a small dachshund - this collar is TRULY tiny, at least twice smaller than the competition. I have put it on a 5 lbs dog and it doesn’t weigh them down. It also works. It beeps and vibrates through a cycle until the dog gets the message. I do wish it came with a zap too, but alas, there is no perfect product. It works with my dogs 90% of the time, and trust me this is better than most similar collars. After trying one, I came back yesterday and bought seven more - one for every dog in the house. A life saver. Thank you, manufacturer, for making a small collar that works!