have been doing some reading and now know what ferning means, and also what that part of the FF chart really means.

These are the 2 types ive found so far
DONNA Fertility Tester
REUSABLE mini-microscope for self-testing. Lets you know within 5 minutes, utilising a few drops of saliva, if you are fertile or not. Precision 68X Power Magnification lens, 98% accurate, Safe, simple and easy to use, Sold in over 30 Countries since 1995, Clinically tested.

Maybe Baby
Mini microscope for determining a woman's fertile and infertile period. Allows an exact determination of the fertile period for predicting conception easily and quickly by detection of the estrogen level in saliva. The so-called "fern-phenomenon" was discovered in 1957 by doctors in Italy. These physicians discovered that the level of the sex hormone estrogen could be detected through visual observation of the dried saliva sample on a microscope slide. At high levels such as those present during ovulation, the crystallized estrogen exhibits a pattern resembling fern leaves. Maybe Baby is a precision instrument that contains a microscope lens to examine a saliva sample under illumination from an LED light source. When estrogen is present, a fern leaf pattern is observed through the viewfinder.

Questions
Have you used any of the these and were they useful for you?
What have you + or - about their use?
Did you use alone or with other Ovulation tests?

Oh, and Dh question: can we use a normal microscope? as add the word help to concieve and he thinks the price goes up