A DOUBLE-STRENGTH BLUEING SOLUTION DESIGNED FOR BLUEING HIGHLY POLISHED STEEL PARTS AND HARDENED STEELS CONTAINING NICKEL AND CHROME ALLOYS (EXCEPT STAINLESS). SUPER BLUE® EXTRA STRENGTH GUN BLUE IS THE BLACKEST BLUE. USE CAUTION TO CONFINE THE SOLUTION TO THE AREA TO BE REBLUED, AS IT WILL HAVE AN EFFECT ON THE EXISTING BLUE.