בדיקת ביוץ

The latest in ovulation testing is the Ovulation watch, which can predict 4-5 days prior to ovulation and significantly increase "fertile" days beyond existing testing. It works by sensing chloride ions from the sweat of the body. There is no color change, but a chemical analysis occurs. My shalah is, what is the Ravs psak with wearing such a watch on Shabbos. And would it make a difference in an eruv or not.

For more info, see https://www.ovwatch.com/ one will have to clarify the nature of the mechanism of action in order to answer the shabbos question.

thanking the Rav Shlita in advance.

sincerely,