Quote Originally Posted by Waterlogged View Post
Then what the heck was on the top of the Swiftech GTX?...and OP, what is aluminum on the HK?
"The housing is CNC machined out of billet aluminum and receives two plating's for a lifetime protection against corrosion: electroless nickel plating (MIL-C-26074E grade B) and Zinc Cobalt plating (ASTM B 840-99 grade 6)."


Maybe it was the Zinc Cobalt first then the nickel