Took my 4 month old basset to a basic training course. I bought a 14 inch long 1/4 to 1/2 mm slip chain. It does a fantastic job on focusing on healing and not letting her nose lead the way! I have had no luck contacting the trainer due to the holidays. I looked on line and have only found the smallest at 3mm. Bought one but it did not have the same effect. She was pulling all the way and it does not stay put under the chin. Do you have any suggestions for me? Signed unwilling romping with a nose to the ground basset!