I bought 2 pairs of danskin tights, and apparently they're reinforced the heel and toe area. I know this because those areas don't match the rest of the tight.  I had a old pair without the reinforced heel/toe that I loved, but lost. So i bought these as replacements.  They're great tights but i used to wear them to dance and work.  Now they're only suitable for dance and the reinforced area is visible even in my ballet shoes. Surely they can reinforce those areas AND make them match!!