Fertility/ovulation tests

What is the difference between fertility test strips and ovulation test strips? I bought the starter ovulation pack than bought refills but accidentally bought fertility refills and just used it in my digital meter. It fits in there, and it showed a blinking smiley face like the ovulation test would have. So I’m just really confused which test strip I should go by- ovulation or fertility. 🤷🏻‍♀️ it seems to me like they both work and can tell me when I’m at a high peak. Sooo can someone tell me which I’m supposed to use, or if it even matters? Thank you in advance

Andrea