Humane and not HURTINg – This prong collars for dogs are smooth and rounded to ensure that no harm comes to your pet and provides gentle pinching sensation to train them which is similar to how a mother dog corrects her puppies using her teeth and at the same time it also can ensure that your pet will pull significantly less while walking o Pulling While Walking or Travel No need to scream at a dog or punish itYou only have to pull the training collar and the dog will stop immediately The training collar is great for training aggressive dogs Strong And ReliableIts necessary to use when you need to add some links you cant take it apart easily either your pet dog Be the pack leader with this safe and effective training collar ALL SIZESSmall Diameter 25 mm and length 14 inch Medium Diameter 30 mm and length 16 inch Large Diameter 35 mm and length 18 inch X-Large Diameter 40 mm and length 20 inch Please contact us to ask for a help if you dont know the exact size 100% SATISFAcTIONOur mission is to let all pet owners enjoy every second with their pets If you have any questions about the product please consult our customer service immediately we will help you within 24 hours