I used it for about 3 months and didn't have any luck with it. It didn't show ferning even though blood tests and OPKs confirmed i was ovulating.

I followed the instructions to the letter, so I don't think it was anything I was doing wrong.

Like Tracey, I borrowed mine and was glad I didn't pay the $60-$80 they charge for them. I wouldn't recommend it. I'd recommend OPKs and temping.