After 15 months of breastfeeding, AF is back [grin] (I'm sure the novelty will wear off pretty quick [wink]). I've used 2 different ovulation prediction calculators and got different windows [hmm] thinking of getting an OPK. I like the look of the clear blue one... It looks fool proof with the smiley face rather than some others. Is it a one use type thing like a pregnancy test? Any OPKs in particular recommended? First DC took 6 months so venturing into OPKs.