Since my dog is adult I buy this necklace and it works nickel! Really, he never had ticks as he had the necklace. Normally it takes 6 or 5 months. Little trick! If you have small dogs not worth buying the format 48 cm. Take the large format, cut half of the collar, keep the rest in the pocket, cast good air, be sure to close the bag and keep it in its box. Then use a paper clip to attach the collar. Even if you think it's crazy it works nickel! It is the vet who advised me! You will save money. I bought a necklace for years.
