The semen detection test is a real evidence test, not a consumer toy. Forensic scientists use these tests in the field and in laboratories. It is an acid phosphtase test. Your order includes a single semen test strip, a pair of sterile cotton swabs, a pair of nitrile gloves and directions. Moisten Stain with water Rub stain with provided cotton swab. Rub the moistened swab onto test strip. Semen is present if it turns purple immediately.