I'm afraid she didn't say and I didn't ask. Last year a different vet (same surgery) recommended the tic collar which Evie wore quite successfully. To be honest that is what I went back for this year but saw a different vet who said that she would really recommend bravecto as a much more superior product to the collar. So that's what we came away with. I must say I didn't really like the collar (although Evie didn't seem to mind) as I felt sorry for her, what with that on plus her usual collar and in addition the halti collar when she goes out in lead. It all seemed a bit bulky.Can I ask why your vet reccomended it? Did he /she explain how it works? Just wondering because mine doesnt even stock it and only recommends deterrent type treatments.