I got this pack of blades from Art of Shaving when I bought my Futur. They're made by PPI in St. Petersburg Russia. While it appears that they are out of production and not readily available for a decent price, it seems PPI has brought blades back after not producing them for a while. The Super Iridiums and Silver Blues appeared to dry up for a while but then came back so it's possible these blades may become readily available again. The first razor I tried these in was my Futur. Before trying these, I used an Astra SP in the Futur for a few days so I'd have a baseline to compare with. The sharpness felt very similar to the Astra for me but smoothness of the Gillette was amazing. This Gillette blade also beat the Astra's longevity. I got 4 shaves from the Gillette and probably could have got a 5th but didn't want to risk irritation. Although the Gillette was losing some sharpness, it still felt smooth. The Astra started to feel a bit rough on the 3rd shave. The second razor I tried the Gillettes in was my Muhle R89. While the blade seemed to work ok in the Muhle, it felt less sharp than an Astra. Still nice and smooth but I had to go over some spots several times to get a close shave. It seems this blade works better for me in a more aggressive razor. After 2 shaves, I moved the blade over to my Weber Bulldog. The Weber feels downright aggressive to me with an Astra SP loaded but with the Gillette Platinums, it had a beautiful smooth feel to it. The blade on its 3rd and 4th shaves felt sharp enough. No tugging on my chin yet and way, way more smooth than the Astra. The Gillette blade and the Weber Bulldog are a great match. Best blade I've used in that razor so far. A few hours after the 4th shave my face felt a very tiny bit irritated so I banked the blade and didn't try for a 5th shave. The next razor I tried was a Gillette Slim Adjustable on 5. The blade worked well. Not quite as well an in the Weber but pretty acceptable. The next morning I went to turn the razor up to 6 and found the blade covered in rust. These blades may require a little more care than most. It was a bit disappointing to only get 1 shave out of it but I'll be more careful with the next 2 blades. Next up was the Merkur 39c slant. The Gillette Platinum's "sharp enough and ultra-smooth" feel is really pretty amazing so I hoped the slant would give the blade just a little boost. Also, since most blades seem to last longer in my slant, I was hoping for a nice long run on the last couple blades I had. Unfortunately, the blades didn't feel any sharper in the slant and I think they performed better in the Slim and much better in the Weber. So, I'll just use up the last 2 blades in the Weber and move on. A little bit of searching and I've found some of these blades available at ridiculously high prices. I don't think they're worth that. In fact, if they come back at $25/100, I may still not buy them. They're probably better for a person who has an average beard. If you're like me and have a thick, coarse beard they feel like they need to be a little sharper.