A double-strength bluing solution designed for bluing 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 re-blued, as it will have an effect on the existing blue. Ships with 25-30 Westlake Market 3" Patches and 25 cotton swabs and backed by Westlake Market's quality product guarantee.