Birchwood Casey Perma Gun Blue ( 2oz Tube )
A double strength blueing solution for polishing steel parts and hardened steels.The Perma Blue solution is for touch-ups as well as complete re-blueing. Designed for blueing mirror polished steel parts and for hardened steels that contain nickel and alloys. Perma Blue liquid gun blue is the blackest blue and penetrates the hardest steel instantly. Apply with a swab to a clean rust-free surface.