How do FairLife products have so much protein without adding protein?

FairLife is a company that makes many dairy products such as milk and protein shakes. I have linked a couple of their products below. ​ They are notorious for have a very high amount of protein and low amount of sugar yet still tasting good compared to many other high protein beverages. The FairLife drinks are also usually only 14oz/serving, so the volume isn't very large either. Is this something to do with the processing? I've never come across nutrition facts like these. ​ [https://fairlife.com/core-power-brand/elite-chocolate-protein-shake/](https://fairlife.com/core-power-brand/elite-chocolate-protein-shake/) [https://fairlife.com/ultra-filtered-milk-14oz/fairlife-chocolate-2-ultra-filtered-milk-14oz/](https://fairlife.com/ultra-filtered-milk-14oz/fairlife-chocolate-2-ultra-filtered-milk-14oz/) Edit: People in the comments are talking about how they use “ultra-filtration”. I have not heard of this used a technical term. Does anyone know the exact method they use?