works and makes buying jewelry less of a guessing game [SEP] i just recently found out i have a nickel allergy according to my dermatologist both real and costume jewelry can have nickel mixed into the metal along with belt buckles and snaps on pants etc so he suggested i buy this to carry with me to test jewelry before i buy it i just whip this little test kit out of my purse and swab the jewelry before i commit to buying it the solutions fit into the provided prescription style bottle along with a few q tip cotton swabs which you have to provide all you do is put drops of solution a and drops of solution b on the tip of a swab and wipe it across the metal for several seconds if the swab turns pink it is not a bright pink so be sure to look closely it contains nickel this sure beats breaking out into itchy blisters