Review on Foresto (Elanco) collar against ticks and fleas for dogs up to 8kg gray by Felicja Stechnij ᠌

Hello, dog weight 6700, puppy 11 months old. I bought this collar about a month ago based on reviews and recommendations from friends. We live in a private house next door to cats that are not processed. The dog still scratches, just like with a flea bite, grasps sharply and irregularly, which is not typical for allergies. The collar is fixed on the neck according to all the rules indicated in the instructions - only two fingers pass. The coat is clean, I do not observe dandruff (black color of wool). Why it continues to scratch I do not know. Maybe someone can give me a hint. As for the rest, I can’t say anything, I have a first dog, I put on a collar for the first time.