I found that earlier. When I click on it it just sent me to Brownells. Kind of like an Amazon trick of listing something and then sending you to another site to complete the sale. Welcome to 2023 internet sales.
that's weird. I just looked in my cabinet and I have a 1/2 bottle of Pilks and a 1/2 bottle of Brownell's. Must be living well. Just need to get some rifles done to the point that they need bluing.
You might try Laural Mt. Forge's rust blue or browning solutions (they are the same). They work fine for me, but I mix them 50:50 with distilled hydrogen hydroxide. Too aggressive otherwise for the routine that I use.