The cheapies from Amazon or early-pregnancy-tests.com work fine. I'm on pregnancy #4 and got pregnant first month each time when using these. Test twice a day to make sure you don't miss the surge.
I used the advanced Clearblue OPK. Worked for 3 positive pregnancies (hoping this one sticks).
Anonymous
05/17/2015 22:51
Subject: Best Ovulation Prediction Kit (OPK)
My husband and I are about to start TTC for #2. What is the best brand of OPK to use? Should we use Advanced OPK? These did not exist when we had our first child. TIA.