I think the sleeve I ordered for my 2023 MacBook Pro (16-inch) was really beautiful. I loved the slim tailored look (color, style, and feel of the Woolenex fabric), the zippers, the soft plush interior, and the material that was placed between the Woolenex fabric (outer layer) and the soft plush interior (inner layer). Whatever it is, I’m guessing this middle layer is some kind of plastic material that is designed to be thick enough to give some stiffness to the sleeve (which helps the sleeve to retain its shape while reducing the risk of water penetrating the sleeve from the outside) but not so thick as to make the sleeve rigid and bulky.
I’m returning the sleeve, however, because I think there is either a design flaw with the sleeve itself or a quality control problem with the particular sleeve I received. Although the Woolenex outer layer of the sleeve is sleek, trim, and appears to be carefully fitted, the middle layer (which I’m guessing is some kind of plastic) was slightly but noticeably wrinkled in some areas under the Woolenex layer: if I run my hand over the surface, some areas feel smooth, but some feel wrinkled beneath the Woolenex.
If you could come up with a different material for the middle layer—one that still gives some desirable stiffness to the sleeve and keeps out water, but that doesn’t look and feel wrinkled— then the sleeve would be perfect!