are you talking about the ovulation kit wiht the smiley faces?
actually many women come home from relaxing vacaiton pregnant because of the sheer fact that they are having fun and relaxing and the body feels comfortable. you can check on a free website to see if you should be fertile during your honeymoon. you just need to know your average cycle time, like are you an average 28 days?
If you are talking about the actual monitor, it is nothing but JUNK!! I bought one a few years ago, and nothing....finally got a BFP without it but M/C. I think the BEST way to detect O is with the smiley face OPKs....They are right on with my temperature shift and everything, the monitor was never right. I always got peaks on CD 12, but never had a temp shift until CD 20.....So if you haven't already bought one, don't waste your money...Try the smileys!!
I have a love/hate relationship with my CBEFM. Yes, they do work. But, they are expensive to use. They can only be used with fmu. They must be used within 3hrs of the same time as the 1st use. They can only be used once per day. If your cycle runs long, it will quit asking for sticks after you already used 20 of them.
If your cycles are consistant it is a lot cheaper and easier to use opks. A lot of people like the smiley ones. I find they are very $ as well. I use the cheap ones (I test 2 or 3x a day) then when I get a pos, I dip a smiley one to see what is does. If is pos, I only used one of the smileys and got off a lot cheaper :)
I have one too. It is very helpful to pin-point ovulation, if you have an irregular cycle length. I do BBT charting as well and noticed that the ovulation prediction on both the monitor and the chart coincides. But they are expensive though.