The ceramic beads integrated into the necklace disturb the tick's receptors, making it impossible for the tick to detect the dog. They limit parasite infestation and make it possible to reduce the applications of anti-parasitic products. The necklace is available in three sizes: XS - S: for a neck circumference of 14-32 cm M - L: for a neck circumference of 26-44 cm XL: for a neck circumference of 40-60 cm Additional information: Like any pet collar, once taken out of the pouch, put it around your pet's neck and, using the clasp, adjust its length, making sure there is a space of about 2 cm between the neck and the collar. Duration of effectiveness: The cord: about 2 years. Pearls: about 10 years Eco-Friendly Objective Zero waste Vegan Cruelty-free (Our product can replace disposable products/Our product is recyclable/Its packaging is recyclable or can have a new use)