Check Mate Infidelity Test Kit - 10 Tests. The 5 minute infidelity test kit is scientifically formulated to actually monitor your spouse's sexual activity outside of the relationship by detecting traces of semen that are left in the undergarments after sex. "If they did it, it's there". The CheckMate 5 Minute Infidelity Test Kit created the underwear testing revolution in 1999 and was the first product or service of its kind to be offered to consumers. Described by some as "The ultimate men's product" CheckMate is the non destructive home use semen detection test used on women's underwear to instantly uncover evidence of sexual activity outside of the relationship. Yes or no results are obtained immediately without staining, cutting, or damaging the article in any way.Because men continue to secrete small amounts of semen after ejaculating traces of dried semen stains will almost always be present in their undergarments after sex. Even if a man uses a condom during sexual intercourse or even if he only had oral sex performed on himself there will still be traces of semen in his underwear. These dried semen stains can live on as evidence for very long periods of time on unwashed articles of clothing and because of this any item that you think may have been stained as the result of recent sexual activity can quickly and easily be tested with CheckMate.