This is 100% Leather, not a leather layer glued on a plastic case. By soaking the leather in warm water it becomes soft and can be shaped to a good degree with just a bit of pressure. The best part is that the leather then holds the shape once fully dry and also becomes harder and stiffer.
3D modeling and printing is a great way to make molds at home, some parts could have been easily made out of wood with just few tools of course and would have done the job just as well or possibly better.
Thanks to MilD_26 for the case model of my smartphone: https://www.thingiverse.com/thing:4155972 I did not model the phone all by myself as I don’t have calipers at hand. But of course it can be done if you want to do this and can’t find one online. This is the Fusion360 file if you want to take a closer look at the press parts: https://a360.co/2xJXM2k
For those asking where to find tools: I bought mine some years ago when I was starting to make leather sheaths. I went for the cheapest I was able to find. Have been working great so far! Can’t find exactly the one I have but I listed some in my amazon storefront that are pretty much the same and any similar ones will work aswell. https://www.amazon.com/shop/blackbeardprojects It’s affiliate marketing so if you order something from here you’ll help the channel for free! Thank you!