When Levis changed the 512 from real cotton denim to thin part-cotton, I was disappointed, because the usual 512 offers no winter warmth at all.  I was skeptical when I ordered these, but was surprised to find they have a high cotton content and the fabric has substance.  Hopefully, Levis will return to its heavier cotton fabric in all of its waist-high jeans.  Not everyone is looking for low-riders.