Saliva Ovulation Tests (such as the popular maybe baby) detects the levels of estrogen in your saliva to help determine your most fertile time of your cycle.
 
You apply saliva (spitting or licking) to the slide and wait for 5 minutes.  This is best done first thing in the morning before eating, drinking or brushing yoru teeth.  Then you place the slide underneath the magnifying scope.  You are looking for a ferning pattern which indicates ovulation.
 

According to studies, saliva ovulation predictor tests are around 98% accurate once you learn to read the ferning pattern. Most people like saliva ovulation predictors because they are re-usable and easy-to-use.

Maybe Baby saliva ovulation test
Maybe Baby saliva ovulation test
$21.65
Time Left: 12h 5m
Lady-Q Saliva Ovulation Tester
Lady-Q Saliva Ovulation Tester
$0.01
Time Left: 2d 6h 32m