This is a kit of 5 single use tests for the identification of Human Semen in an unidentified stain. Ever have a stain a wonder what it might be? or just need some confirmation? well this is the test for you then. This test is intended to test for human semen and does so by testing for PSA (prostate specific antigens). This kit is very easy to use and will show results in just 10 minutes. Use the tests that laboratories use at a fraction of the cost.