Source: https://www.amazon.com/Hartz-Ultra-Guard-Treatment-Kittens/dp/B00XM15DOM/ref=as_li_ss_tl?&imprToken=GEKPoJVNjBKnWzsKDGxHqw&slotNum=8&linkCode=sl1&tag=catover05-20&linkId=b66d4b29543808539376b7ed6eb1e8d5