Has anyone used "Steel F/X" for SS Forced Patina?

[Spillproof]

Anyone familiar with this product?

STAINLESS STEEL PATINAS Archives

Stainless Steel Patinas for Color Case-Hardening of Firearm Parts and Knife Blades.

steelfxpatinas.com

I'm interested but don't want to spend the $43 (minimum) if someone has a better product recommendation.

 

[stonemedusa6264]

I saw their products for the first time like a week ago. The only problem is I can only find info on their product from them. Also interested if anyone has experience with their stuffs?